Phase separated photochromic systems

Abstract

A photochromic system comprises liquid crystals in a photochromic polymer matrix. The photochromic system shows improved photochromic kinetics of a photochromic dye. The fade-back half-time speed of the photochromic dye significantly increases, especially at lower temperature, when the photochromic composition contains dispersed liquid crystal droplets. The fatigue resistance of a lens prepared from the photochromic composition containing dispersed liquid crystal droplets also improves when such lens is further coated with at least one antireflective coating.

Description

Patent Application110000-603 / PCTPHASE SEPARATED PHOTOCHROMIC SYSTEMSRELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 692,003 filed September 6, 2024, entitled Phase Separated Photochromic Systems, which is hereby incorporated herein by reference in its entirety.BACKGROUND

[0002] Photochromic optical articles, for example but not limited to, ophthalmic lenses, motorsport visors, non-corrective eyewear, sportswear, goggles, windows, variable density filters for optical devices, typically contain photochromic dye molecules.

[0003] Photochromic dye molecules absorb light, such as sunlight and / or UV light, which may lead to a reversible conformational / structural change or isomerization resulting in a ring opening and bond rearrangement of the photochromic dye molecules. As a result, the photochromic optical articles may change colors or darken depending on the intensity and / or brightness of the incident light. The darkness of the photochromic articles fade if the exposure to sunlight and / or UV light is reduced or absent and in the absence of sunlight and / or UV light, the photochromic articles return to their leuco or colorless clear state.

[0004] The darkening or coloration of the photochromic lenses takes place quickly, for example, within about a minute after exposure to bright sunlight. The fading of the photochromic lenses to their leuco or clear state takes somewhat longer when the exposure to the sunlight or UV light is reduced or absent. Controlling dye fading rate may be obtained by changing the structural attributes of a specific dye molecule, i.e. altering a substituent on the dye molecule to increase fading speed. However, fine-tuning dye characteristics through synthesis of different dye structures may be a long and arduous task, and critically, these characteristics may be difficult to predict accurately.- 1 - I IPG-1 -160249Patent Application110000-603 / PCT

[0005] Accordingly, there exists a need to develop a photochromic host system having efficient photochromic dye fading rate in which the fading behavior / kinetics of the dye is optimized. The dyes may be generally dispersed in a polyurethane matrix and the formulation may be laminated between two polycarbonate sheets. Examples herein describe formulation modification through addition of liquid crystalline additives in the current formulation to alter the overall kinetics of photochromic articles. One example benefit of lies in the fact that the overall performance of the photochromic system can be modified using a simple additive - without requiring synthetic modifications of the dyes / monomers or major overall formulation change.SUMMARY

[0006] Disclosed herein are various examples of a photochromic coating which may include a polymer matrix containing a photochromic dye and liquid crystals. The photochromic coating may exhibit improved photochromic kinetics of the photochromic dyes. In some examples, the photochromic coating may exhibit an improved photochromic dye fading rate, especially at lower temperatures, for example but not limited to, at about 5 degrees centigrade.

[0007] Disclosed herein are examples of a method of forming a polymer dispersed liquid crystal (PDLC) photochromic laminate. The laminate may be formed by coating a photochromic polymer dispersed liquid crystal formulation on a corona treated sheet, for example but not limited to, a polycarbonate sheet, and curing the sheet to form the polymer dispersed liquid crystal photochromic laminate.

[0008] In some examples, the polymer dispersed liquid crystal formulation may comprise a polymer matrix comprising a photochromic dye dispersed with low melting liquid crystal droplets.

[0009] In some examples, the polymer matrix may comprise a polymer composition which may be formed by mixing a diisocyanate component with a polyol, a catalyst, a chain extender, and a photochromic dye.- 2 - IIPG-1 -160249Patent Application110000-603 / PCT

[0010] In some examples, the polymer matrix may be comprised of either a UV curable composition or a thermally curable formulation that includes liquid crystals and dyes that do not participate in the chemical reaction that cures the polymer matrix.

[0011] In some examples, the photochromic coating comprising the polymer matrix and liquid crystals may exhibit improved half-life and fading speed of the photochromic dye compared to previous systems and methods.

[0012] In some examples, a photochromic lens prepared with embedded liquid crystal droplets in the photochromic layer may exhibit improved fade-back half time, especially at lower temperature, for example but not limited to 5°C.

[0013] In some examples, a photochromic system prepared with embedded liquid crystal droplets in the photochromic layer may be a photochromic coating or a photochromic lens or a photochromic laminate which exhibit improved fade-back half time, especially at lower temperature, for example but not limited to at 5°C.

[0014] In some examples, a photochromic lens prepared with embedded liquid crystal droplets in the photochromic layer may cross the benchmark 113hours threshold of TSSS (Thermal, Shock, Sweat, and Sebum) test.

[0015] In some examples, a photochromic lens prepared with embedded liquid crystal droplets in the photochromic layer may exhibit improved fatigue resistance when at least one surface of the photochromic lens is coated with an anti-reflecting coating.

[0016] In some examples, there may be no visible difference in color coordinates between a control lens having no embedded liquid crystal droplets and a test photochromic lens prepared with embedded liquid crystal droplets.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following figures are included to illustrate certain example aspects of the present disclosure and should not be viewed as exclusive or limiting. The subject matter- 3 - IIPG-1 -160249Patent Application110000-603 / PCT disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to one having ordinary skill in the art and having the benefit of this disclosure. The present disclosure references the drawings as follows:

[0018] Fig. 1 is a schematic representation of polymer dispersed liquid crystals (PDLC) with photochromic dyes according to some examples.

[0019] Fig. 2 shows liquid crystal droplets formation through optical microscopy during curing of a formulation having 50% liquid crystals and 50% polymer according to some examples.

[0020] Fig. 3 is a table (1 ) illustrating the viscosity values of the liquid crystals induced photochromic polymer composition (CEF-160) during mixing and after the addition of the 5-20 wt% of the liquid crystals according to some examples.

[0021] Fig. 4 is a representative FT-IR spectrum of a final formulation comprising the polymer matrix and liquid crystals before curing of the final formulation according to some examples.

[0022] Fig. 4A represents FT-IR spectra illustrating the evolution of the curing step to indicate the complete consumption of the isocyanate group from the diisocyanate and gradual formation of the carbamate linkage indicating the completion of the curing according to some examples.

[0023] Fig. 4B is an expanded view of the left-side of the IR spectrum of Fig. 4A according to some examples.

[0024] Fig. 4C is an expanded view of the right-side of the IR spectrum of Fig. 4A according to some examples.- 4 - IIPG-1 -160249Patent Application110000-603 / PCT

[0025] Fig. 5 is a table (2) illustrating performance of the laminates prepared with liquid crystals formulation (E7) and photochromic formulation (CEF 160) at about 23°C and about 5°C according to some examples.

[0026] Fig. 6 is a table (3) illustrating exemplary T-peel strength of the laminates prepared with liquid crystals formulation (E7) and photochromic formulation (CEF 160) and produced on the lamination line and cured at 70 degrees centigrade and laminates cured at 50 degrees centigrade in an oven according to some examples.

[0027] Fig. 7 is a photograph showing semi-finished lenses according to some examples.

[0028] Fig. 8 is a table illustrating performance of the lenses prepared with liquid crystals formulation (E7) and photochromic formulation (CEF 160) shown in Fig. 7 according to some examples.

[0029] Fig. 9 is a table (5) illustrating compositions of the laminates formed of liquid crystals (HNG, HTD and E7) and photochromic formulation (S 3G B) and the curing conditions of the laminates according to some examples.

[0030] Fig. 10 is a table (6) illustrating experiments performed on the control lenses and laminates made with the photochromic formulation S 3G B with respect to the lenses and laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0031] Fig. 11 is a table (7) illustrating the T-Peel test results of the laminates made with the control photochromic formulation S 3G B with respect to the laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0032] Fig. 12A is a table (8) illustrating the activated transmittance of the laminates made with the control photochromic formulation S 3G B with respect to the laminates- 5 - IIPG-1 -160249Patent Application110000-603 / PCT made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0033] Fig. 12B is a graphical representation of the activated transmittance of the laminates of Fig. 12A, table 8, according to some examples.

[0034] Fig. 13 is a table (9) illustrating the fade-back half time of the laminates of Fig. 12A, table 8 at 5 °C, 23°C and 35°C according to some examples.

[0035] Fig. 14A is a graphical representation of fade-back half time of the laminates of Fig. 12A, table 8 at 5 °C, 23°C and 35°C according to some examples.

[0036] Fig. 14B expands the graphical representation of fade-back half time of the laminates of Fig. 12A, table 8 at 23°C according to some examples.

[0037] Fig. 15 represents fade-back transmittance of the laminates made with the control photochromic formulation S 3G B with respect to the laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0038] Fig. 16A represents the activated color response at 23°C for the laminates made with the control photochromic formulation S 3G B with respect to the laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0039] Fig. 16B represents the activated color response at 5°C for the laminates made with the control photochromic formulation S 3G B with respect to the laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0040] Fig. 16C represents the activated color response at 35°C for the laminates made with the control photochromic formulation S 3G B with respect to the laminates- 6 - IIPG-1 -160249Patent Application110000-603 / PCT made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0041] Fig. 17A is a table (10) illustrating the activated transmittance of the lenses made with the control photochromic formulation S 3G B with respect to the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0042] Fig. 17B is a graphical representation of the activated transmittance of the lenses of Fig. 17A, table 10, according to some examples.

[0043] Fig. 18A is a table (11 ) illustrating the fade-back half time of the lenses of Fig. 17A, table 10 at 5 °C, 23°C and 35°C according to some examples.

[0044] Fig. 18B is a graphical representation of fade-back half time of the lenses of Fig. 17A, table 10 at 5 °C, 23°C and 35°C according to some examples.

[0045] Fig. 19A represents the activated color response at 23°C for the lenses made with the control photochromic formulation S 3G B with respect to the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0046] Fig. 19B represents the activated color response at 23°C for the films / laminates and lenses made with the control photochromic formulation S 3G B with respect to the films / laminates and lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0047] Fig. 19C represents the activated color response at 5°C for the lenses made with the control photochromic formulation S 3G B with respect to the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.- 7 - IIPG-1 -160249Patent Application110000-603 / PCT

[0001] Fig. 19D represents the activated color response at 35°C for the lenses made with the control photochromic formulation S 3G B with respect to the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0048] Fig. 20 shows fade-back transmittance of the lenses made with the control photochromic formulation S 3G B with respect to the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B at 5 °C, 23°C and 35°C according to some examples.

[0049] Fig. 21 shows comparison of the fade-back transmittance of the lenses and films / laminates made with the control photochromic formulation S 3G B with respect to the lenses and films / laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B at 5 °C according to some examples.

[0050] Fig. 22 shows the lenses made with the control photochromic formulation S 3G B and the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B in clear states according to some examples.

[0051] Fig. 23A shows the lenses made with the control photochromic formulation S 3G B and the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B in activated states according to some examples.

[0052] Fig. 23B shows the conditions (-1 °C and sunny day) at which the photographs in activated states were taken of the lenses made with the control photochromic formulation S 3G B and the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0053] Figs. 24A and 24B shows the TSSS (temperature, shock, sebum, sweat) test of the lenses made with the control photochromic formulation S 3G B and the lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.- 8 - IIPG-1 -160249Patent Application110000-603 / PCT

[0054] Fig. 25 shows the AR (antireflective, EX3) coated lenses made with the control photochromic formulation S 3G Brn and the AR (antireflective, EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G Brn in clear states according to some examples.

[0055] Fig. 26 shows the AR (EX3) coated lenses made with the control photochromic formulation S 3G B and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B in activated states at 24°C under sunny condition, according to some examples.

[0056] Fig. 27 shows photographs at 30 sec fade-back, 60 sec fade-back and 90 sec fade-back of the AR (EX3) coated lenses made with the control photochromic formulation S 3G B and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0057] Fig. 28is a table (13) illustrating the fatigue resistance after 72h and 144h of the polycarbonate laminates made with the control photochromic formulation S 3G B and the laminates made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0058] Fig. 29A represents transmittance after Oh, 72h and 144h irradiation of the polycarbonate laminate made with the control photochromic formulation S 3G B according to some examples.

[0059] Fig. 29B represents transmittance after Oh, 72h and 144h irradiation of the polycarbonate laminate made with the liquid crystals HNG and photochromic formulation S 3G B according to some examples.

[0060] Fig. 29C represents transmittance after Oh, 72h and 144h irradiation of the polycarbonate laminate made with the liquid crystals HTD and photochromic formulation S 3G B according to some examples.- 9 - IIPG-1 -160249Patent Application110000-603 / PCT

[0061] Fig. 29D represents transmittance after Oh, 72h and 144h irradiation of the polycarbonate laminate made with the liquid crystals E7 and photochromic formulation S 3G B according to some examples.

[0062] Fig. 30 is a table (14) illustrating the fatigue resistance after 72h and 144h of the molded lenses made with the control photochromic formulation S 3G B and the molded lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0063] Fig. 31 A represents transmittance after Oh, 72h and 144h irradiation of the molded control lens made with the photochromic formulation S 3G B according to some examples.

[0064] Fig. 31 B represents transmittance after Oh, 72h and 144h irradiation of the molded lens made with the liquid crystals HNG and photochromic formulation S 3G B according to some examples.

[0065] Fig. 31 C represents transmittance after Oh, 72h and 144h irradiation of the molded lens made with the liquid crystals HTD and photochromic formulation S 3G B according to some examples.

[0001] Fig. 31 D represents transmittance after Oh, 72h and 144h irradiation of the molded lens made with the liquid crystals E7 and photochromic formulation S 3G B according to some examples.

[0066] Fig. 32 is a table (15) illustrating the fatigue resistance after 72h and 144h of the AR (EX3) coated lenses made with the control photochromic formulation S 3G B and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G B according to some examples.

[0067] Fig. 33A represents transmittance after Oh, 72h and 144h irradiation of the AR (EX3) coated lens made with the control photochromic formulation S 3G B according to some examples.- 10 - IIPG-1 -160249Patent Application110000-603 / PCT

[0068] Fig. 33B represents transmittance after Oh, 72h and 144h irradiation of the AR (EX3) coated lens made with the liquid crystals HNG and photochromic formulation S 3G B according to some examples.

[0069] Fig. 33C represents transmittance after Oh, 72h and 144h irradiation of the AR (EX3) coated lens made with the liquid crystals HTD and photochromic formulation S 3G B according to some examples.

[0070] Fig. 33D represents transmittance after Oh, 72h and 144h irradiation of the AR (EX3) coated lens made with the liquid crystals E7 and photochromic formulation S 3G B according to some examples.

[0071] Fig. 34 shows photographs of the AR (EX3) coated control lens and AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) with respect to control lens without AR (EX3) coating and lenses made with the liquid crystals (HNG, HTD and E7) without AR (EX3) coating in clear states after 144h in weathering chamber according to some examples.

[0072] Fig. 35shows photographs of the AR (EX3) coated control lens and AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) with respect to control lens without AR (EX3) coating and lenses made with the liquid crystals (HNG, HTD and E7) without AR (EX3) coating in activated states after 144h in weathering chamber according to some examples.DETAILED DESCRIPTION

[0073] It will be appreciated by persons skilled in the art that the present disclosure is not limited to what has been particularly shown and described herein. A variety of modifications and variations are possible in view of the teachings herein without departing their scope, spirit, or intent.

[0074] While different examples may be described in this specification, it is specifically contemplated that any of the features from the different examples can be- 11 - IIPG-1 -160249Patent Application110000-603 / PCT used and brought together in any combination. In other words, the features of different examples can be mixed and matched with each other. Hence, while every permutation of features from different examples may not be explicitly shown or described, it is the intention of this disclosure to cover any such combinations, especially as may be appreciated by one of skill in the art.

[0075] The terminology used in this disclosure should be interpreted in a permissive manner and is not intended to be limiting. In the drawings, like numbers refer to like elements. Unless otherwise noted, the term “about” is defined to mean plus-or-minus 10% of a stated value.

[0076] Polymer dispersed liquid crystals or PDLC’s find wide range of applications in the field of light control. PDLC’s may be formulated by dispersing liquid crystal droplets in a polymer matrix to form polymer / liquid crystal composites. The characteristics of this composite system can be modified by modifying the microstructures of the polymer and / or the liquid crystals. The polymer / liquid crystal composites can be further enhanced / modified for targeted applications by doping with materials such as nanoparticles, surfactants, and dyes. Photochromic dye doped polymer dispersed liquid crystals may have several applications, including but not limited to, flexible transparent displays, light shutters, privacy and smart windows, switching gratings, sensors, microlenses, lasers, smart food packaging, electrically switchable high-fold-helix spiral phase plates and biomedical devices.

[0077] The general process of fabrication of PDLC film involves mainly two different classes, for example, fabrication of PDLC film through emulsion techniques and fabrication of PDLC film through phase separation techniques.

[0078] In the emulsion techniques, an emulsion-type PDLC, also known as NCAP (encapsulated liquid crystal), may be formulated by solvent evaporation of an emulsion of liquid crystals in an aqueous solution of a water-soluble polymer, for example but not limited to, polyvinyl alcohol (PVA) or a mixture of PVA / glycerin. Water soluble polymers may be utilized in the preparation of such emulsion PDLC’s.- 12 - IIPG-1 -160249Patent Application110000-603 / PCT

[0079] In the phase separation techniques, a homogeneous, liquid, single phase mixture containing, for example, the liquid crystals and the monomers / prepolymer, may be prepared. During polymer solidification or curing, all the liquid crystals molecules may be expelled from the polymeric phase. The expelled liquid crystals may form droplets and remain embedded or dispersed in the polymeric phase or film.

[0080] The phase separation technique can be classified into three categories, for example, polymerization-induced phase separation (PIPS), temperature-induced phase separation (TIPS), and solvent-induced phase separation (SIPS).

[0081] In the polymerization-induced phase separation (PIPS), the liquid crystals and monomers may be mixed into a homogeneous solution and placed in an appropriate device. Non-limiting examples of such appropriate devices may include privacy window films, light shutters, flexible displays etc. The polymerization may then be initiated either by heating the solution (thermally initiated PIPS) or illuminating the solution, for example, with UV irradiation (photo-initiated PIPS, or P-PIPS).

[0082] In the temperature-induced phase separation (TIPS), the liquid crystals may be mixed with melted thermoplastic polymer and placed in an appropriate cavity of a device. The phase separation may be induced by polymer solidification, such as initiated by cooling.

[0083] In the solvent-induced phase separation (SIPS), a solution or a mixture may be prepared with the polymer, solvent, and a required amount of liquid crystals and then placed in an appropriate device. The droplet formation may be induced by solvent evaporation.

[0084] In some examples of a photochromic system, the kinetics of the photochromic dye (e.g., the dye fading rate) may be influenced through polymer dispersed liquid crystals (PDLC’s) which contains, for example but not limited to, a polymer matrix comprising a photochromic dye and liquid crystals dispersed in the polymer matrix.- 13 - IIPG-1 -160249Patent Application110000-603 / PCT

[0085] Suitable photochromic dyes used in photochromic system may, for example, organic compounds selected from benzopyrans, naphthopyrans, indenonaphthopyrans, spirobenzopyrans, spironaphthopyrans, spirobenzoxzines, spironaphthoxazines, fulgides and fulgimides.

[0086] Among the photochromic compounds identified, naphthopyran and indenonaphthopyran derivatives may exhibit good quantum efficiency for coloring, a good sensitivity and saturated optical density, an acceptable bleach or fade rate, and most importantly good fatigue behavior for use in eyewear. These compounds are available to cover the visible light spectrum from 400 nanometer to 700 nanometer.

[0087] Suitable naphthopyran dyes may be represented by the following generic formulae with the possibility of substitution of the hydrogen atoms at different positions on the aromatic rings with different functional groups (not shown below) to modify the dye behavior:

[0088] In some examples, the systems and methods shown and / or described herein may utilize a polymer dispersed liquid crystal photochromic formulation containing a derivative of naphthopyran dye, for example, an indenonaphthopyran dye as shown below:- 14 - IIPG-1 -160249Patent Application110000-603 / PCT

[0089] In such polymer dispersed liquid crystal photochromic formulation, which is prepared by dispersing liquid crystal mixture in a polyurethane formulation (e.g., as disclosed in U.S. Patent No. 8,906,183, the content of which is incorporated here in its entirety).

[0090] The polyurethane formulation is prepared by mixing component A, for example, prepolymer with hydroxyl end groups (containing an excess of -OH) and component B, for example, prepolymer with isocyanate end groups (containing an excess of -NCO). The ingredients of component A and component B may comprise aliphatic diisocyanates, for example but not limited to, 4,4'-diisocyanato dicyclohexylmethane (H12MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) etc.; a polyol, for example but not limited to, polycaprolactone polyol (CAPA2101A), polyether polyols, polyester polyols, polycarbonate polyols, acrylic polyols etc.; a catalyst to initiate the polymerization, for example but not limited to, dibutyltin dilaurate (DABCO, T-12), dioctyltin dilaureate, bismuth carboxylate, zinc carboxylate, zirconium and aluminum chelates, mixed metal oxides etc.; a chain extender, for example but not limited to, 1 ,4-butanediol, trimethylol propane etc. and liquid crystal mixtures, for example but not limited to, low melting liquid crystals E7, 5CB etc.

[0091] In some non-limiting examples of the liquid crystals in the polymer dispersed liquid crystal photochromic formulation, the liquid crystals may comprise a generic structure as shown below:- 15 - IIPG-1 -160249Patent Application110000-603 / PCT

[0092] In some non-limiting examples, the rigid core of the liquid crystals may comprise of aromatic rings, such as benzene or naphthalene rings, due to their structural rigidity. However, other aromatic or non-aromatic rings, such as but not limited to cyclohexane, thiophene, thiazole, cyclopentane, cyclobutene, bicyclo[2.2.2]octane, benzothiophene, oxadiazole may also be used as the rigid core. In some non-limiting examples, aromatic rings, for example, biphenyl, bithiophene, bipyridine may be bonded to each other to form the rigid core of the liquid crystals.

[0093] In some non-limiting examples, the terminal chain of the liquid crystals may comprise an aliphatic chain of any length or a silane chain. In some non-limiting examples, the linking group of the liquid crystals may comprise ester, thioester, ether, thioether, -C=C-, -N=N-, -CH=CH-, -CH2-CH2-. In some non-limiting examples, the lateral substitution may comprise -H, -Cl, -Br, -CN etc. In some examples, the polar end group may comprise electron withdrawing functional groups, such as but not limited to, -CN, - F, -CF3, -NCS, -Cl, NO2, -SO3R etc.

[0094] Other nonlimiting examples of liquid crystals used in the polymer dispersed liquid crystal photochromic formulation comprises combinations of pi-conjugated aromatic rings, for example, pi-conjugated aromatic rings with core phenylene groups with substitutions (R1and R2) at different positions as shown below with generic formula 1 :- 16 - IIPG-1 -160249Patent Application110000-603 / PCT

[0095] In some examples, the liquid crystals may comprise a combination of substituted phenylene group including pi-conjugated aromatic compounds.

[0096] For example, in a first pi-conjugated aromatic compound, R1may comprise an electron withdrawing group, for example but not limited to, a CN, -F, -NO2, -CFa.-SOsR, -Cl etc. group and R2may comprise a linear alkyl group, for example but not limited to, an alkyl group comprising 5 carbon atoms.

[0097] In a second example of a pi-conjugated aromatic compound, R1may comprise an electron withdrawing group, for example but not limited to, a CN group and R2may comprise a linear alkyl group, for example but not limited to, an alkyl group comprising 7 carbon atoms.

[0098] In a third example of a pi-conjugated aromatic compound, R1may comprise an electron withdrawing group, for example but not limited to, a CN group and R2may comprise a linear alkoxy group, for example but not limited to, alkoxy group comprising oxygen atom and 8 carbon atoms, such as, -O-Cs.

[0099] In a fourth example of a pi-conjugated aromatic compound, R1may comprise an electron withdrawing group, for example but not limited to, a CN group and R2may comprise an aryl substitution, for example but not limited to, an alkyl substituted phenyl group, such as, a phenyl group substituted with 5 carbon atoms such as -Ph-Cs.

[0100] In one non-limiting example, E7 liquid crystal may comprise the following compositions.- 17 - IIPG-1 -160249Patent Application110000-603 / PCT

[0101] In some examples, the polymer matrix of the polymer dispersed liquid crystal photochromic formulation may comprise a prepolymer with isocyanate end groups, another prepolymer with -OH end groups, a catalyst, a chain extender component, and a derivative of naphthopyran dye. The components may be mixed and just before coating, different weight percentages of the liquid crystal mixture may be added in the formulation and vigorously stirred to disperse it. Different weight percentages (with respect to the total weight of the formulation) of liquid crystals of formula 1 may be added to prepare various polymer dispersed liquid crystal photochromic compositions.

[0102] In some examples, 5 weight% of liquid crystals of formula 1 may be added to the polymer matrix to prepare the polymer dispersed liquid crystal photochromic composition. In some examples, 10 weight% liquid crystals of formula 1 may be added to the polymer matrix to prepare the polymer dispersed liquid crystal photochromic composition. In some other examples, 15 weight % and 20 weight% of liquid crystals of formula 1 may be added to the polymer matrix to prepare the polymer dispersed liquid crystal photochromic composition.

[0103] Without being limited to 5, 10, 15 or 20 weight percentages of the liquid crystals in the polymer dispersed liquid crystal photochromic composition, any other possible weight percentages of the liquid crystals can be added to the polymer matrix to prepare the various polymer dispersed liquid crystal photochromic compositions. Also,- 18 - IIPG-1 -160249Patent Application110000-603 / PCT any other combinations of aliphatic diisocyanates, polyols, catalysts, chain extenders, and any other derivative of naphthopyran dye may be used to prepare the polymer matrix.

[0104] In the polymer matrix, naphthopyran dye may be the only aromatic component and other components of the polymer matrix, for example the prepolymers prepared from the components (but not limited to) aliphatic diisocyanates, polyols, catalysts, and / or chain extenders, in the polymer matrix may be aliphatic in nature. Hence, when the liquid crystals, comprising for example pi-conjugated aromatic rings, may be added to the polymer matrix followed by the curing, the resulting system forms, for example but not limited to, a polymer dispersed liquid crystal photochromic composition in which there may be droplets of the liquid crystals trapped in the solid polymer phase where the liquid crystal droplets may be enriched with photochromic dyes.

[0105] The aromatic dye may have a larger propensity to reside in the droplets of the liquid crystals due to the possible TT-TT interactions between the aromatic naphthopoyran dye and the aromatic phenylene backbone containing liquid crystals rather than the aromatic naphthopoyran dye to be residing in the solid polymer matrix containing the aliphatic components. This is schematically represented in Fig. 1 .

[0106] Fig. 1 shows that polymer composition and liquid crystals are mixed together. The liquid crystal droplets may be immiscible in the polymer composition. After curing the polymer may be solidified, for example, as a film. The liquid crystal droplets may be embedded in the solid polymer film, as can be seen in Fig. 2. The aromatic naphthopoyran dye may have a larger propensity to reside in the droplets of the liquid crystals rather than residing in the solid polymer matrix because of the possible TT-TT interactions between the aromatic naphthopoyran dye and the aromatic backbone containing liquid crystals.

[0107] Such a polymer dispersed liquid crystal photochromic composition, as shown in Fig. 1 , may have improved (e.g., faster) photochromic kinetics; as the dyes may be in a more liquid like system rather than being trapped in a solid polymer matrix.- 19 - IIPG-1 -160249Patent Application110000-603 / PCT

[0108] Experimental results:

[0109] As can be seen in the following experimental sections, two types of curable photochromic formulations, such as CEF 160 and S 3G Brown were prepared and mixed with the liquid crystals, for example, E7, HNG, HTD to form the PDLC-laminates and PDLC-lenses to perform the experiments and tests in this application. Laminates are alternatively referred to as films (F) also in this application.

[0110] In each experiment, the PDLC-laminates and lenses were tested against the laminates and lenses made without the polymer dispersed liquid crystals as the control sample such that the efficiency of the PDLC-laminates and PDLC-lenses are clearly visible when compared to the performances of the control sample.

[0111] In the first set of experiments, curable photochromic formulation CEF 160 was mixed with liquid crystal E7 to form the PDLC-laminates and lenses, which were tested against the laminates and lenses made without the polymer dispersed liquid crystals as the control sample.

[0112] In the second set of experiments, curable photochromic formulation S 3G Brown (or Brn / Br / B, as variously mentioned throughout this application) was mixed with liquid crystals E7, HNG, HTD to form the PDLC-laminates and PDLC-lenses.

[0113] In each case, the PDLC-laminates and PDLC-lenses were tested against the control laminates and lenses made with photochromic formulation CEF 160 and S 3G B (without liquid crystal) such that the efficiency of the PDLC-laminates and PDLC-lenses are clearly visible when compared to the performances of the control laminates and lenses.

[0114] In some non-limiting examples, liquid crystals, for example, HNG, HTD, may not contain any cyano (CN) or isocyanate (NCO) groups.

[0115] PDLC-laminates / lenses made with photochromic formulation CEF 160 and E7 liquid crystal:- 20 - IIPG-1 -160249Patent Application110000-603 / PCT

[0116] A standard photochromic formulation (CEF 160, curable photochromic formulation) was prepared and collected one day after mixing. E7 liquid crystal mixture was added (5% / 10% / 15% and 20% on the total weight of the formulation). The resulting formulation was coated on a corona treated polycarbonate sheet. The laminates were cured by a two-step process. In the first step, it was kept at a 60% relative humidity chamber at 23 degrees Celsius (°C) for 4 days. After that, it was placed in an oven at 50°C for 4 days. The consumption of isocyanate was followed by FTIR spectroscopy for the whole length of curing.

[0117] PDLC-laminates / lenses made with photochromic formulation S 3G Brown and 5% total weight of liquid crystals HNG, HTD and E7:

[0118] A standard photochromic formulation (S 3G B, curable photochromic formulation) was prepared by mixing the components, for example, the polymer matrix of the photochromic formulation, which may comprise a prepolymer with isocyanate end groups, another prepolymer with hydroxyl end groups, a catalyst, a chain extender component, photochromic dyes and stabilizers, for example, a derivative of a naphthopyran dye.

[0119] The S 3G B mixture was divided into four containers, as can be seen from Fig. 9 and table 5. The first container (1 ) contained only the mixture S 3G B as a control. In the second container (2), 5% total weight of liquid crystal HNG was added in the mixture S 3G B. The third container (3) contained the mixture S 3G B and 5% total weight of liquid crystal HTD. The fourth container (4) contained the mixture S 3G B and 5% total weight of liquid crystal E7.

[0120] Next, laminates were made from the mixture S 3G B in the first container (1 ) with a laminate ID, S 3G B-C. In the containers 2, 3 and 4, the mixtures of S 3G B and 5% total weight of liquid crystals, for example, HNG, HTD and E7, were kept in a speedy mixture for about 7.5 minutes and laminates were made right after with laminate IDs, S 3G B-HNG, S 3G B-HTD and S 3G B-E7. All the laminates were kept at room temperature (23°C) for 3 days. After that, laminate S 3G B-C was kept in an oven at 70°C- 21 - IIPG-1 -160249Patent Application110000-603 / PCT for 4 days and laminates S 3G B-HNG, S 3G B-HTD and S 3G B-E7 were kept in an oven at 55°C for 4 days before molded into lenses orTSSS (temperature, shock, sebum, sweat) tests and lenses for photochromic properties evaluation.

[0121] Tests were conducted with PDLC-laminates / lenses made with photochromic formulation CEF 160 and E7 liquid crystal:

[0122] Fig. 3 shows Table-1 , which details the viscosity values at different time intervals after mixing the components A and B of the pre-polymer composition. The prepolymer composition is synthesized using, for example but not limited to, the aliphatic diisocyanate, polyol, catalyst, chain extender, and naphthopyran dye, at 25 degrees centigrade and 1 day after mixing the components of the polymer composition at 25 degrees centigrade. Table-1 also shows viscosity values when 5wt%, 10wt%, 15wt% and 20wt% of E7 liquid crystals may be added to the polymer composition. However, it should be appreciated that the range of 5-20 wt% is merely an example, as values outside of that range (either higher or lower) may be used in some examples. Table-1 shows that the viscosity of the formulation generally increases with the addition of higher weight percentages of the liquid crystals.

[0123] Fig. 4 shows an FT-IR spectrum of one of the final formulations before curing. In this spectrum, both cyano and isocyanate peaks are visible. The cyano peaks originate from the liquid crystals, for example but not limited to, from the CN substituted phenylene groups of the liquid crystals. The isocyanate peaks originate from the polymer with isocyanate end groups used in a standard photochromic polymer composition, before commencement of the curing of the polymer composition.

[0124] Fig. 4A shows the gradual evolution of the curing step though a representative FT-IR spectrum after mixing components A and B of the pre-polymers with the liquid crystal composition. FT-IR spectrum in Fig. 4A shows the complete consumption of the isocyanate group (R-N=C=O) from the diisocyanate and gradual formation of the carbamate linkage (H-N-COO) indicating the completion of the curing. Fig. 4B is an- 22 - IIPG-1 -160249Patent Application110000-603 / PCT expanded view of the left-side of the IR spectrum of Fig. 4A and Fig. 4C is an expanded view of the right-side of the IR spectrum of Fig. 4A.

[0125] Fig. 4C shows the gradual diminishment of the isocyanate peaks (R-N=C=O) from the polymer with isocyanate end groups and the unchanged cyano (-CN) peak from the liquid crystals after 4 days of the reaction. Fig. 4B shows the gradual formation of the carbamate peak with the progression of the curing of the standard photochromic polymer composition. As time progressed, the isocyanate peak gradually decreases, indicating that the isocyanate is being consumed by reacting with the polymer with -OH end group (Fig. 4C). With the progress of the reaction, Fig. 4B shows that the carbamate peak strengthens; indicating that the urethane linkages (-NH-COO) of the solid polymer matrix are forming. With the completion of the curing, the isocyanate peak eventually disappears, however, the cyano peak from the liquid crystals remains unchanged even after the curing is complete, as shown in Fig. 4C. This indicates that the liquid crystals might remain unreacted in droplets during the curing process.

[0126] After the curing was complete (the isocyanate peak disappeared on FT-IR), the laminates were subjected to photochromic performance testing, as shown in Table 2 of Fig. 5. Table 2 shows that some of the formulations with added E7 liquid crystals may provide significant improvement of the kinetics of the photochromic dye, for example but not limited to, improved half-life (in seconds) and faster initial fading speed of the photochromic dye.

[0127] In some examples, the photochromic polymer dispersed liquid crystal laminates may show improved half-life (in seconds) and faster initial fading speed of the photochromic dye especially at lower temperatures, for example but not limited to, at about 5 degrees centigrade, as compared to the control gray prepared on the lamination line without any liquid crystals.

[0128] In some examples, the laminates produced on the lamination line may be cured at 70 degrees centigrade. In some other examples, the laminates produced were cured at 50 degrees centigrade in an oven. However, there is no significant difference in- 23 - IIPG-1 -160249Patent Application110000-603 / PCT performance and T-peel strength of the standard laminates, as shown in Fig. 6, Table 3 from the T-peel strength experiments of the laminates produced by these two procedures.

[0129] In some examples, the photochromic polymer dispersed liquid crystal laminates were molded into semi-finished lenses, and they did not show any signs of degradation after molding and retained the photochromic properties, as shown with a semi-finished lens, a semi-finished lens with 5wt% E7, and a semi-finished lens with 10wt% E7 in Fig. 7.

[0130] The performance data of these lenses are tabulated in Fig. 8. Table 4 shows that some of the lenses with added E7 liquid crystals may provide significant improvement of the kinetics of the photochromic dye to have improved half-life (in seconds) and faster initial fading speed of the photochromic dye.

[0131] In some examples, the lenses may show improved half-life (in seconds) and faster initial fading speed of the photochromic dye especially at lower temperatures, for example but not limited to, at about 5 degrees centigrade.

[0132] In some examples, when temperature is higher, for example, at about 35 degrees centigrade, some of the lenses may show improved or faster initial fading speed of the photochromic dye when a higher concentration of liquid crystals may be used in the lens formation. For example, lenses made with 15% liquid crystals may show faster initial fading speed of the photochromic dye as compared to lenses made with 5% or 10% liquid crystals.

[0133] Tests were conducted with PDLC-laminates and lenses made with photochromic formulation S 3G B and 5% total weight of liquid crystals HNG, HTD and E7 for each laminate and lens:

[0134] The PDLC-laminates / lenses made with photochromic formulation S 3G B and 5% total weight of liquid crystals HNG, HTD and E7 were subjected to different tests, for- 24 - IIPG-1 -160249Patent Application110000-603 / PCT example, T-peel test at room temperature in Instron instrument, evaluation of transmittance at activated states at 5°C, 23°C and 35°C in PAT instrument, evaluation of fatigue using PAT, Suntester 1 instrument and TSSS (temperature, shock, sebum, sweat) test for the lenses in Lunaire oven, as shown in tabular form in Fig. 10.

[0135] T-Peel Tests with PDLC-laminates and control laminate:

[0136] T-peel is a test method that measures the peel separation strength of two flexible materials, for example, films or laminates, that have been bonded together with an adhesive.

[0137] The T-peel tests were performed with laminates S 3G B (control) and PDLC- laminates, for example, S 3G B-HNG, S 3G B-HTD and S 3G B-E7, and data were collected with average of three samples. As can be seen from Fig. 11 , table 7, all the PDLC-laminates show comparable average T-Peel force within a range of 4.2 to 4.7kg / cm (with a standard deviation in a range of 0.1 -0.3) as compared to the control laminate S 3G B having average (3 scaleup runs) T-Peel force of 4.6kg / cm (with a standard deviation of 0.2). The Adhesive thicknesses for the control and PDLC- laminates were in a range of 40p to 43p.

[0138] Activated Transmittance of the PDLC-laminates and control laminate:

[0139] Activating the PDLC-laminates and the control laminate and recording the transmittance data when the photochromic dye in both types of laminates is in activated states may provide information whether the presence of the liquid crystals dispersed / em bedded in the photochromic composition of the PDLC-laminates may have any effect on the amount of light transmitted through the PDLC-laminates.

[0140] The activated transmittance data at various temperatures, for example but not limited to, 5°C, 23°C, and 35°C for the PDLC-laminates, for example, S 3G B-HNG, S 3G B-HTD and S 3G B-E7 against the control laminate S 3G B are tabulated in table 8 and plotted in Figs. 12A-12B. It can be seen from table 8 and 12A-12B, the activated- 25 - IIPG-1 -160249Patent Application110000-603 / PCT transmittance values of the PDLC-laminates and the control are comparable at 5°C, 23°C, and 35°C.

[0141] In some non-limiting examples, by adding 5% of the total weight of the liquid crystals, for example, HNG, HTD and E7, to the photochromic composition, for example, S 3G B, a reduced total solid weight percentages of the dye may be needed as compared to the total solid weight percentages of the dye needed in the control samples (without liquid crystal) to have comparable activated transmittance. For example, the total solid weight percentages of the dye needed in the photochromic composition having liquid crystals, HNG, HTD and E7, may be about 3.01% as compared to the total solid weight percentages of the dye of about 3.16% in the control samples to have the comparable activated transmittance. In some nonlimiting examples, 5% ofthe total weight of the liquid crystals is equivalent to about 11.9% of the solids in the photochromic PDLC composition.

[0142] Fade-back half time of the PDLC-laminates and control laminate:

[0143] In the context of photochromic laminates, fade-back half time refers to the time it takes for these photochromic laminates to return from their darkened states to the clear states after being removed from UV light exposure.

[0144] Darkening of the photochromic laminates takes place quickly, for example, within about a minute after exposure to light. However, the fading of the photochromic laminates to their leuco or clear state takes longer when the light source is reduced or absent. The slower fade-back time of the photochromic dyes is exacerbated at lower temperatures (for example, at 5°C), where the fade-back time may increase by factors of 10 or more. Hence, one aspect of this application is to improve the fade-back time, especially at lower temperature, for example but not limited to, at 5°C.

[0145] The fade-back performances of the PDLC-laminates, for example, S 3G B- HNG, S 3G B-HTD and S 3G B-E7, are tabulated in table 9, Fig. 13 with respect to the control laminate (no liquid crystals present in the photochromic formulation) at various temperature ranges, for example but not limited to, at 5°C, 23°C and 35°C.- 26 - IIPG-1 -160249Patent Application110000-603 / PCT

[0146] In some non-limiting examples, the PDLC-laminates may show improved fade- back half time (in seconds) and faster fading speed of the photochromic dye from darkened state to clearer state especially at lower temperatures, for example but not limited to, at about 5°C.

[0147] As can be seen from table 9, the PDLC-laminates, S 3G B-HNG, S 3G B-HTD and S 3G B-E7, show significant improvement of the kinetics of the photochromic dye to have improved fading back half time (in seconds) and faster initial fading speed of the photochromic dye, especially at relatively lower temperature, for example, at 5°C, as compared to the control (S 3G B-C).

[0148] In some examples, the PDLC-laminates may still show improved half-life (in seconds) and faster initial fading speed of the photochromic dye at relatively higher temperature, for example but not limited to, at 23°C, as compared to the control (S 3G B-C). However, at higher temperatures, for example, at 23°C and 35°C, the difference in fade-back half time may be gradually less prominent between the PDLC-laminates and the control laminate.

[0149] The graphical representations of the fade-back half time (in seconds) with respect to the temperature, as shown in Figs. 14A and 14B, clearly exhibit fade-back half time is much faster for the PDLC-laminates, S 3G B-HNG, S 3G B-HTD and S 3G B-E7, especially, at 5°C, as compared to the control laminate (S 3G B-C). The difference in half fading time may be less prominent between the PDLC-laminates and the control laminate when the experiment temperatures are higher, for example but not limited to, 23°C or 35 °C.

[0150] Fade-back transmittance of the PDLC-laminates and control laminate:

[0151] In some non-limiting examples, the PDLC-laminates, S 3G B-HNG, S 3G B- HTD and S 3G B-E7, may show higher fade-back transmittance, especially at lower temperatures, for example but not limited to, at about 5°C, when compared to the control laminate, S 3G B-C. In some other examples, there may be hardly any difference in fade-- 27 - IIPG-1 -160249Patent Application110000-603 / PCT back transmittance between the PDLC-laminates and the control laminate, when the experiment temperatures are higher, for example but not limited to, 23°C or 35 °C.

[0152] The fade-back transmittance of the PDLC and control laminates are shown in Fig. 15. At lower temperatures, for example, at about 5°C, the PDLC-laminates may show higher fade-back transmittance as compared to the control laminate. However, the difference in fade-back transmittance may be negligible between the PDLC- laminates and the control when the experiment temperatures are higher, for example but not limited to, 23°C or 35 °C.

[0153] In some non-limiting examples, the activated color coordinates of the PDLC- laminates and control laminate remain comparable at different temperature ranges, for example but not limited to temperatures ranging from lower to higher, such as, at 5°C, 23°C or 35 °C.

[0154] Fig. 16A shows the activated color coordinates of the PDLC-laminates and the control at 23°C. Fig. 16B shows the activated color coordinates of the PDLC-laminates and the control 5°C. Fig. 16C shows the activated color coordinates of the PDLC- laminates and the control 35°C. The activated color coordinates of the PDLC-laminates and the control are comparable at temperatures ranging from lower to higher, for example but not limited to, at 5°C, 23°C or 35 °C.

[0155] Activated Transmittance of the PDLC-lenses and control lens:

[0156] Activating the PDLC-lenses and the control lens with an UV-light source and recording the transmittance data when the photochromic dye in both types of lenses is in activated states may provide information whether the presence of the liquid crystals dispersed / em bedded in the photochromic composition of the PDLC-lenses may have any effect on the amount of light transmitted through the PDLC-lenses.- 28 - IIPG-1 -160249Patent Application110000-603 / PCT

[0157] PDLC laminates, S 3G B-HNG, S 3G B-HTD and S 3G B-E7 and control laminate, S 3G B-C, were molded into lenses for photochromic properties evaluation, such as, evaluation of the transmittance in the activated states.

[0158] The activated transmittance data at various temperatures, ranging from lower to higher temperatures, for example but not limited to, 5°C, 23°C, and 35°C for the PDLC- lenses, for example, S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7 against the control lens, S 3G Br-C (no liquid crystals), are tabulated in table 10 and plotted in Fig. 17B. It can be seen from table 8 and 17B, the activated transmittance values of the PDLC- lenses and the control lens are comparable at lower temperature, for example but not limited to at 5°C.

[0159] Although, the activated transmittance of the PDLC-laminates (S 3G B-HNG, S 3G B-HTD and S 3G B-E7) varies slightly (about 1 % at 35°C) from the control laminate, S 3G B-C (as shown in Figs. 12A and 12B) at relatively higher temperatures, for example but not limited to, at 23°C, and 35°C, the activated transmittance of the PDLC-lenses (S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7) varies significantly (about 3-4% less darkness at 23°C and 35°C for lenses) from the control lens, S 3G Br-C, as can be seen from Figs. 17A and 17B.

[0160] Fade-back half time of the PDLC-lenses and control lens:

[0161] As for photochromic lenses, fade-back half time refers to the time it takes for these photochromic lenses to return from their darkened states to the clear states after being removed from UV light exposure.

[0162] It is common knowledge that fading of the photochromic lenses to their leuco or clear state takes longer when the light source is removed, especially at lower temperatures, for example but not limited to at 5°C. Hence, one aspect of this application is to improve the fade-back time for the photochromic lenses and to review if the presence of the liquid crystals in the photochromic layer of the lens may improve the fade-back time, especially at lower temperature.- 29 - IIPG-1 -160249Patent Application110000-603 / PCT

[0163] The fade-back performances of the PDLC-lenses, for example, S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7 are tabulated in table 11 , Fig. 18A with respect to the control lens, S 3G Br-C (no liquid crystals present in the photochromic formulation) at various temperatures, ranging from lower to higher temperatures, for example but not limited to, at 5°C, 23°C and 35°C.

[0164] In some examples, the PDLC-lenses may show improved half-life (in seconds) and faster initial fading speed of the photochromic dye especially at lower temperatures, for example but not limited to, at about 5°C.

[0165] As can be seen from table 11 , Fig. 18B, the PDLC-lenses, S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7, show significant improvement of the kinetics of the photochromic dye to have improved half-life (in seconds) and faster initial fading speed of the photochromic dye, especially at relatively lower temperature, for example, at 5°C, as compared to the control lens (S 3G Br-C).

[0166] In some non-limiting examples, however, at higher temperatures, for example but not limited to, at 23°C and 35°C, the difference in half fading time may be less prominent between the PDLC-lenses and the control lens.

[0167] The graphical representations of the half fading time (in seconds) with respect to the temperatures, as shown in Fig. 18B, illustrates that the half fading time is much faster for the PDLC-lenses, S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7, especially, at 5°C, as compared to the control lens (S 3G Br-C). The difference in half fading time may be less prominent between the PDLC-lenses and the control lens when the experiment temperatures are higher, for example but not limited to, at 23°C or 35 °C.

[0168] In some non-limiting examples, the activated color coordinates of the PDLC- lenses and control lens remain comparable at different temperature ranges, for example, temperatures ranging from lower to higher, for example but not limited to, at 5°C, 23°C and 35 °C.- 30 - IIPG-1 -160249Patent Application110000-603 / PCT

[0169] Fig. 19A shows the activated color coordinates of the PDLC-lenses (S 3G Brn HNG L, S 3G Brn HTD L and S 3G Brn E7 L) and the control lens (S 3G Brn C L) at 23°C.

[0170] Fig. 19B simultaneously plots the activated color coordinates of the PDLC- lenses (S 3G Brn HNG L, S 3G Brn HTD L and S 3G Brn E7 L) and the control lens (S 3G Brn C L) with respect to the PDLC-laminates (S 3G Br-HNG, S 3G Br-HTD and S 3G Br-E7) and the control laminate (S 3G Br- C) at 23°C.

[0171] It can be seen from Figs. 19A and 19B that the activated color coordinates of the PDLC-lenses and control lens and the PDLC-laminates and control laminate remain comparable at 23°C.

[0172] Fig. 19C shows the activated color coordinates of the PDLC-lenses and the control lens at 5°C. Fig. 19D shows the activated color coordinates of the PDLC-lenses and the control lens at 35°C.

[0173] The activated color coordinates of the PDLC-lenses and the control lens are comparable at temperatures ranging from lower to higher, for example but not limited to, at 5°C, 23°C or 35 °C.

[0174] Fade-back transmittance of the PDLC-lenses and control lens:

[0175] In some non-limiting examples, the PDLC-lenses, S 3G Brn HNG, S 3G Brn HTD and S 3G Brn E7, may show higher fade-back transmittance, especially at lower temperatures, for example but not limited to, at about 5°C, when compared to the control lens, S 3G Brn C. In some other non-limiting examples, there may be hardly any differences in fade-back transmittance between the PDLC-lenses and the control lens, when the experiment temperatures are higher, for example but not limited to, at 23°C or 35 °C.

[0176] The fade-back transmittance of the PDLC-lenses and control lens are shown in Fig. 20. At lower temperatures, for example, at about 5°C, the PDLC-lenses show- 31 - IIPG-1 -160249Patent Application110000-603 / PCT higher fade-back transmittance as compared to the control lens. However, the difference in fade-back transmittance may be negligible between the PDLC-lenses and the control lens when the experiment temperatures are higher, for example but not limited to, at 23°C or 35°C.

[0177] Fade-back transmittance of the PDLC-lenses / PDLC-laminates and control lens / laminate at 5°C:

[0178] In some non-limiting examples, the PDLC-lenses, for example, S 3G Brn-HNG 5C L, S 3G Brn HTD 5C L and S 3G Brn E7 5C L; and PDLC-laminates, for example, S 3G Brn 5C, S 3G Brn HTD 5C and S 3G Brn E7 5C, may show higher fade-back transmittance, especially at lower temperatures, for example but not limited to, at about 5°C, when compared to the control lens, S 3G Brn 5C and control laminate, S 3G Brn C 5C L.

[0179] The fade-back transmittance of the PDLC-lenses vs control lens and PDLC- laminates vs control laminate are shown in Fig. 21 . At lower temperatures, for example, at about 5°C, the PDLC-lenses and PDLC-laminates show higher fade-back transmittance as compared to the control lens and control laminate. However, the fading back speed, or in other words, the percentages of transmittance, of the PDLC-lenses and PDLC-laminates decrease at the same rate with the control lens / laminates, as can be seen from Fig. 21 . Therefore, it may be concluded that the decrease in percentages of transmittance of the PDLC-lenses and the PDLC-laminates is not related to the presence of the liquid crystals in the corresponding lens / laminates.

[0180] In some non-limiting examples, Figs. 22, 23A and 23B show the appearance of the PDLC-lenses in clear states (Fig. 22) and in activated states (Fig. 23A) when the PDLC-lenses were activated at -1 °C under sunny conditions, Fig. 23B) as compared to the control lens C (without any liquid crystals). In clear states, the PDLC-lenses appear very similar with light bluish tint as compared to the control lens (C, Fig. 22). In activated states, the PDLC-lenses have very similar appearances having same colors and darknesses at -1 °C under sun.- 32 - IIPG-1 -160249Patent Application110000-603 / PCT

[0181] TSSS (Thermal, Shock, Sebum, Sweat) tests of the PDLC-lenses and the control lens:

[0182] The TSSS test investigates the effect of sebum, temperature and moisture on a photochromic lens. In this test, artificial sebum is applied on the lens. The lenses are then placed in a humidity oven and stress is applied using ring clamps. The lenses are then periodically inspected and the time when delamination is initiated is noted. Longer time needed for the delamination to start indicates better adhesion of the different layers.

[0183] TSSS experiment with the PDLC-lenses and control lens:

[0184] Fig. 24A shows the TSSS experiment of the PDLC-lenses, for example, S 3GB HNG, S 3G B HTD and S 3G B E7, and control lens, S 3G B C. In the first step of the experiment, the Lunaire oven (Lunaire CEO-917-4-C or Associated Environmental ZHD- 421 ) temperature was set to 65°C and relative humidity of the oven was set to 100RH%. Fig. 24A plots the ratio of the number of lenses remaining without delamination, N(t) / the total number of lenses, N(0) with respect to time in hours.

[0185] In the TSSS experiment, the sebum, artificial human sebaceous and sweat secretion were placed into an oven for at least 15 minutes to soften the contents.

[0186] In the next steps, the PDLC-lenses and control lens were set on their centers, convex sides down, on a flat surface near the edge of a lab bench and loosened clamps were placed around the lenses such that the segment-lines in each lens were aligned parallel to the bolts of the clamps on the side opposite the bolts. Next, proper torque setting was selected to be 50cN m=5.1 kgf cm with a torque screwdriver.

[0187] In the next steps, first, the sebum (which was set at lower temperature on a hot plate with constant stirring) was applied with a cotton-tipped applicator to the edges of the front side of the PDLC-lenses and control lens.

[0188] The PDLC-lenses and control lens, in a plastic basket, were placed in the humidity oven. After a maximum of 113 hours, the clamps with lenses were taken out of- 33 - IIPG-1 -160249Patent Application110000-603 / PCT the humidity oven and inspected for delamination. The maximum delamination radius was measured without removing lenses from clamps.

[0189] The TSSS test data for the PDLC-lenses (S 3GB HNG, S 3G B HTD and S 3G B E7) and control lens (S 3G B C) are shown in Fig. 24B (table 12). Table 12 shows that all the PDLC-lenses and control lens pass the threshold of 113 hours for the TSSS test.

[0190] In some nonlimiting examples, some of the PDLC lenses, for example, S 3G B HTD and S 3G B E7, however, show that the first failure or delamination starts between 113 hours and 135 hours. The control lens, S 3G B C, having no polymer dispersed liquid crystal in the photochromic formulation, shows the highest survival rate (180 hours) as compared to the PDLC-lenses, and the hours to start first delamination for the PDLC- lenses are in a range of 153 hours to 169 hours.

[0191] AR-coated PDLC-lenses and control lens:

[0192] Lenses made with polymer dispersed liquid crystals in the photochromic composition or control lens without having any polymer dispersion in the photochromic composition may further be coated with an anti-reflective coating (AR) to reduce glare as well as to provide superior scratch protection and resistance to smudges and water on the surface of the both types of lenses.

[0193] In some non-limiting examples, lenses having dispersed liquid crystals (HNG, HTD and E7) in the photochromic formulation (S 3G Brn) and the control lens made with photochromic formulation, S 3G Brn, without having any liquid crystals dispersed, may further be coated with an anti-reflecting coating (AR coating, as it will be referred to throughout the rest of the specification).

[0194] In some non-limiting examples, the AR-coating may be EX3. In some nonlimiting examples, the EX3-AR coating may provide superior scratch protection and resistance to smudges and water on the surface of the lenses in addition to reduced glare.- 34 - IIPG-1 -160249Patent Application110000-603 / PCT

[0195] Fig. 25 shows clear states photographs of the AR (EX3) coated lens made with the control photochromic formulation S 3G Brn and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G Brn. Fig. 26 shows activated states photographs of the AR (EX3) coated lens made with the control photochromic formulation S 3G Brn and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G Brn at 24°C under sunny conditions.

[0196] Fig. 27 shows 30 sec fade-back, 60 sec fade-back and 90 sec fade-back photographs of the AR (EX3) coated lens made with the control photochromic formulation S 3G Brn and the AR (EX3) coated lenses made with the liquid crystals (HNG, HTD and E7) and photochromic formulation S 3G Brn after the light source was removed from these lenses.

[0197] Fatigue resistance of the PDLC-lenses and control lens:

[0198] Photochromic film, laminate, or lenses are subject to degradation by common environmental factors such as exposure to UV radiation, heat, water / humidity, and oxygen. The photochromic dyes are also susceptible to photo-oxidative damage or degradation, leading to permanent discoloration and / or loss of the ability to change between the clear and colored isomers. This is called dye fatigue. The fatigue resistance or the improvement of the fatigue of a dye is important for the performance of a photochromic laminate or lens.

[0199] Another aspect of the present application is to investigate the fatigue resistance of the photochromic dyes in PDLC-laminates / PDLC-lenses and control lens.

[0200] In some non-limiting examples, the PDLC-laminates, such as, S 3G B F HNG, S 3G B F HTD, S 3G B F E7, and PDLC-lenses (molded), such as, S 3G B L HNG, S 3G B L HTD, S 3G B F E7, show poorer fatigue resistance, especially after 144hours, as compared to the control laminate, S 3G B F C or control lens, S 3G B L C, which have no liquid crystal dispersed in the photochromic formulation. However, the fatigue- 35 - IIPG-1 -160249Patent Application110000-603 / PCT resistance performances of the PDLC-lenses may significantly improve when these lenses are coated with AR-coating, for example but not limited to EX3 AR-coating, as compared to the PDLC-lenses having no EX3 AR-coating.

[0201] Fig. 28 in table 13 shows that fatigue resistance of the PDLC-laminates, such as, S 3G B F HNG, S 3G B F HTD, S 3G B F E7, as compared to the control laminate, S 3G B F C, after 72hours and 144 hours under fatigue condition. In this test, the lenses are irradiated with radiation mimicking sunlight for 144 hours and then the photochromic performance is measured. The obtained value is compared with a lens that has not been exposed to the radiation. It can be seen from table 13 that the PDLC-laminates, S 3G B F HNG, S 3G B F HTD, S 3G B F E7, may have lost their photochromic activities after 144 hours from the percentage of transmission data after 144 hours under fatigue condition. PDLC-laminates, S 3G B F HNG, S 3G B F HTD, S 3G B F E7, also show poorer fatigue resistance after 72 hours as compared to the control laminate, S 3G B F C.

[0202] Fig. 29A shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the control polycarbonate laminate S 3G B F C made with the control photochromic formulation. Fig. 29B shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the polycarbonate laminate S 3G B F HNG made with the liquid crystals HNG and photochromic formulation S 3G B. Fig. 29C shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the polycarbonate laminate S 3G B F HTD made with the liquid crystals HTD and photochromic formulation S 3G B. Fig. 29D shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the polycarbonate laminate S 3G B F E7 made with the liquid crystals E7 and photochromic formulation S 3G B. It can be seen from Figs. 29B-29D, the PDLC- laminates, S 3G B F HNG, S 3G B F HTD, S 3G B F E7, have lost their photochromic activities after 144 hours since the average percentage of transmission is above 96 after 144 hours under fatigue condition.- 36 - IIPG-1 -160249Patent Application110000-603 / PCT

[0203] Fig. 28 in table 13 shows that after 144 hours of irradiation, the percentage of fatigue for S 3G B F HNG, S 3G B F HTD and S 3G B F E7 laminates are, for example, 98.3%, 96.0 % and 97.2% respectively. At this point, after 144hours of irradiation, the PDLC-laminates have lost their photochromic activities since almost all the light may pass through these laminates without getting absorbed in the photochromic layers of the laminates as can be seen from the %T values from Figs. 29B-29D of the PDLC-laminates S 3G B F HNG, S 3G B F HTD and S 3G B F E7.

[0204] In some examples, the percentage of fatigue for a laminate or lens is calculated by following the formula below:Activity Loss atXHours (« / .) = 100

[0205] The percentage of activity loss or fatigue % at x hours, for example, at 72 hours and 144 hours for the PDLC-laminates, for example, S 3G B F HNG, S 3G B F HTD and S 3G B F E7, in Fig. 28 in table 13 are calculated by the area under the photochromic curve at 0 hours (from Fig. 29B-29D) and then subtracts it from the area under the curve at 144 hours (or 72 hours). The difference is the measure of % fatigue at 72 hours or 144 hours for these laminates.

[0206] In some non-limiting examples, the same formula is applied to calculate the percentage of activity loss or fatigue % at x hours, for example, at 72 hours and 144 hours for the PDLC-lenses and PDLC-lenses coated with anti-reflective coating, for example but not limited to, EX3 anti-reflective coating.- 37 - IIPG-1 -160249Patent Application110000-603 / PCT

[0207] Fig. 30 in table 14 shows that fatigue resistance of the PDLC-lens (molded), such as, S 3G B L HNG, S 3G B L HTD, S 3G B L E7, as compared to the control lens, S 3G B L C, after 72hours and 144 hours under fatigue condition. It can be seen from table 15 that the PDLC-lenses, S 3G B L HNG, S 3G B L HTD, S 3G B L E7, show poorer fatigue resistance, especially after 144hours, as compared to the control lens, S 3G B L C.

[0208] However, the fatigue resistance of the PDLC-lenses appears to be better than the fatigue resistance of the PDLC-laminates after 144hours under fatigue condition when compared to the control lens, S 3G B L C. In some non-limiting examples, among the three PDLC-lenses, S 3G B L HNG, S 3G B L HTD, S 3G B L E7, PDLC-lens, S 3G B L HTD, shows the best fatigue resistance (% of transmittance, 53.0) and PDLC-lens, S 3G B L E7, shows the worst fatigue resistance (% of transmittance, 83.9) after 144 hours under fatigue condition.

[0209] Fig. 31 A shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the control lens S 3G B L C made with the photochromic formulation S 3G B. Fig. 31 B shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the molded PDLC-lens S 3G B L HNG made with the liquid crystals HNG and photochromic formulation S 3G B. Fig. 31 C shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the molded PDLC-lens S 3G B L HTD made with the liquid crystals HTD and photochromic formulation S 3G B. Fig. 31 D shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the molded PDLC-lens S 3G B L E7 made with the liquid crystals E7 and photochromic formulation S 3G B. It can be seen from Fig. 31 C, the PDLC-lens, S 3G B L HTD, shows the best fatigue resistance (% of transmittance, 53.0) after 144 hours under fatigue condition as compared to the other PDLC-lenses, S 3G B HNG L and S 3G B L E7.

[0210] Fig. 32 in table 15 shows that fatigue resistance of the AR-coated (EX3) PDLC- lens, such as, S 3G B L HNG EX3, S 3G B L HTD EX3, S 3G B L E7 EX3, as compared to the AR-coated (EX3) control lens, S 3G B L C EX3, after 72hours and 144 hours under- 38 - IIPG-1 -160249Patent Application110000-603 / PCT fatigue condition. It can be seen from table 16 that the AR-coated PDLC-lenses, S 3G B L HNG EX3, S 3G B L HTD EX3, S 3G B L E7 EX3, show significantly improved fatigue resistance after 144hours under fatigue condition as compared to the PDLC-lenses having no AR (EX3) coating, for example, S 3G B L HNG, S 3G B L HTD, S 3G B L E7 (as shown in Fig. 30, table 14).

[0211] In some non-limiting examples, among the three AR-coated PDLC-lenses, S 3G B L HNG EX3, S 3G B L HTD EX3, S 3G B L E7 EX3, AR-coated PDLC-lens, S 3G B L E7 EX3 shows comparatively worse fatigue resistance (% of transmittance, 43.9) after 144 hours under fatigue condition. Without being limited by any theory, the applicant considers that the presence of cyano (-CN) functional group in the E7 liquid crystal may be detrimental to the fatigue resistance of the AR-coated PDLC-lens, S 3G B L E7 EX3 and the PDLC-lens, S 3G B L E7 (Fig. 30), without having any EX3 AR-coating.

[0212] Fig. 33A shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the AR-coated control lens S 3G B L C EX3 made with the control photochromic formulation, S 3G B. Fig. 33B shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the AR-coated PDLC-lens, S 3G B L HNG EX3, made with the liquid crystals HNG and photochromic formulation S 3G B. Fig. 33C shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the AR- coated PDLC-lens, S 3G B L HTD EX3 made with the liquid crystals HTD and photochromic formulation S 3G B. Fig. 33D shows percentage of transmission spectra after Oh, 72h and 144h irradiation of the AR-coated PDLC-lens S 3G B L E7 EX3 made with the liquid crystals E7 and photochromic formulation S 3G B. It can be seen from Fig. 33D, AR-coated PDLC-lens, S 3G B L E7 EX3, shows the worst fatigue resistance (% of transmittance, 43.9) after 144 hours under fatigue condition as compared to the other AR-coated PDLC-lenses.

[0213] Fig. 34 compares clear states photographs of the AR (EX3) coated control lens and AR (EX3) coated PDLC-lenses made with the liquid crystals (HNG, HTD and E7) with respect to the clear states photographs of the control lens without having any- 39 - IIPG-1 -160249Patent Application110000-603 / PCTAR coating and PDLC-lenses made with the liquid crystals, but without having any AR coating after 144h in weathering chamber.

[0214] Fig. 35 compares activated states photographs of the AR (EX3) coated control lens and AR (EX3) coated PDLC-lenses made with the liquid crystals with respect to the activated states photographs of the control lens without having any AR coating and PDLC-lenses made with the liquid crystals, but without having any AR coating after 144h in weathering chamber. Fig. 35 shows that no uniform activation is observed for the AR- coated PDLC-lens and PDLC-lens having no AR-coating made using liquid crystal mixture, E7.

[0215] In some examples, the polymer dispersed liquid crystal photochromic formulation may comprise a polymer matrix and fluorinated liquid crystals mixture with wide nematic range to influence the performance of the photochromic dye.

[0216] In some examples, the polymer dispersed liquid crystal photochromic formulation may comprise a polymer matrix and smectic liquid crystals to influence the performance of the photochromic dye.

[0217] In some examples, the polymer dispersed liquid crystal photochromic formulation may comprise a stabilizer package to increase the fatigue resistance of the photochromic system.

[0218] In some examples, the performance of the photochromic dye in the polymer dispersed liquid crystal photochromic formulation may be influenced by the dielectric anisotropy of the liquid crystals.

[0219] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that- 40 - IIPG-1 -160249Patent Application 110000-603 / PCT the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.- 41 - IIPG-1 -160249

Claims

Patent Application110000-603 / PCTWhat is claimed is:

1. A photochromic system, comprising: a polymer matrix containing a photochromic dye; and a liquid crystal mixture; wherein the photochromic system shows a faster fade back half time as compared to a photochromic system without having any liquid crystal mixtures in the polymer matrix.

2. The photochromic system of claim 1 , wherein the liquid crystal mixture comprises chemical structures containing an aromatic backbone.

3. The photochromic system of claim 2, wherein the aromatic backbone comprises a substituted core phenylene group in the chemical structures of the liquid crystal mixture.

4. The photochromic system of claim 3, wherein the core phenylene group is substituted with an electron withdrawing group in the chemical structures of the liquid crystal mixture.

5. The photochromic system of claim 3, wherein the core phenylene group is substituted with a cyano group in the chemical structures of the liquid crystal mixture.

6. The photochromic system of claim 1 , wherein droplets of the liquid crystal mixture are dispersed in the polymer matrix.

7. The photochromic system of claim 1 , wherein a lens or a laminate formed with the photochromic system shows a faster fadeback halftime as compared to a lens or laminate having no liquid crystal mixtures in the polymer matrix.

8. The photochromic system of claim 7, wherein the lens or the laminate formed with the photochromic system shows the faster fadeback half time at a lower temperature.- 42 - IIPG-1 -160249Patent Application110000-603 / PCT9. The photochromic system of claim 8, wherein the lens or the laminate formed with the photochromic system shows the faster fadeback half time at about 5 degrees centigrade.

10. An optical lens, comprising: a photochromic film enclosed between two protective resin layers to form a laminate; the laminate is embedded in a resin to form the optical lens; and at least one surface of the optical lens is coated with an anti-reflective coating; wherein the photochromic film, comprises: a polymer matrix containing a photochromic dye; and a liquid crystal mixture dispersed in the polymer matrix; wherein the optical lens is about 1.8 to 2.0 times more efficient in fatigue resistance as compared to a similar optical lens without having any anti-reflective coating.11 . The optical lens of claim 10, wherein a percentage of fatigue of the photochromic dye is in a range of about 29% to 43% after 144 hours of UV irradiation.

12. The optical lens of claim 10, wherein a percentage of fatigue of the photochromic dye is in a range of about 15% to 19% after 72 hours of UV irradiation.

13. The optical lens of claim 11 , wherein the percentage of fatigue of the photochromic dye is about 30% after 144 hours of UV irradiation when the liquid crystal mixture is devoid of a cyano functional group.

14. The optical lens of claim 12, wherein the percentage of fatigue of the photochromic dye is about 15% after 72 hours of UV irradiation when the liquid crystal mixture is devoid of a cyano functional group.- 43 - IIPG-1 -160249Patent Application110000-603 / PCT15. A method of producing a polymer dispersed liquid crystal photochromic laminate, comprising: forming a polymer composition, adding a photochromic dye to the polymer composition; adding liquid crystal droplets to the polymer composition, coating the polymer composition having the photochromic dye and the liquid crystal droplets on a film, curing the film to form the photochromic laminate having embedded liquid crystal droplets.

16. The method of claim 15, wherein the polymer composition is formed by mixing a hydroxyl terminated prepolymer with an isocyanate terminated prepolymer.

17. The method of claim 15, wherein the curing of the film further comprises exposing the film to about 60% relative humidity.

18. The method of claim 15, wherein adding the liquid crystal droplets to the polymer composition further comprises adding 5-20 weight% of the liquid crystals to a total weight of the formulation.

19. The method of claim 15, wherein coating the formulation on the film further comprises coating the formulation on a corona treated polycarbonate film.

20. The method of claim 15, wherein embedding the liquid crystal droplets on the photochromic laminate provides a faster fadeback speed at a lower temperature for the photochromic dye.- 44 - IIPG-1 -160249

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