A photochromic glass

Abstract

The present invention discloses a photochromic glass, belonging to the technical field of glass, which comprises a first glass layer, an organic-inorganic composite layer and a second glass layer arranged in sequence from top to bottom. The organic-inorganic composite layer is obtained from an organic-inorganic composite film material; the organic-inorganic composite film material comprises the following raw materials in mass percentage: 0.5-2% of photochromic powder, 0.5-1% of functional material, 20-30% of plasticizer, and the balance is polyvinyl butyral; the present invention uses photochromic powder with fast light response and anti-fatigue property as the basic photochromic material, cesium tungsten bronze nanoparticles with spectral selective absorption as the near-infrared light shielding material, and polyvinyl butyral as the film carrier material. By using ultrasonic dispersion and high-speed ball milling equipment, the cesium tungsten bronze nanoparticles are made into functional materials; through mixing, casting and extrusion into films, and compression molding, the finally obtained photochromic glass has good weather resistance and color change response speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass, and particularly relates to a photochromic glass. Background Art

[0002] Photochromic glass generally has a "sandwich" structure. The external support protective layer is made of glass material, and the middle layer is a film formed by a photochromic material and an organic film-forming substance. Photochromic materials are divided into organic photochromic materials and inorganic photochromic materials. Organic photochromic materials have problems such as poor thermal stability, easy aging, and weak weather resistance. Although inorganic photochromic materials have the characteristic of high stability compared with organic photochromic materials, the surface effect and electrostatic effect are prone to cause agglomeration, making it impossible to be evenly dispersed in the organic matter, greatly affecting the film-forming uniformity. And once phase separation occurs in the composite material of nanoparticles, the performance of the functional layer will rapidly decay, seriously affecting the quality of the photochromic window glass.

[0003] Currently, the technical means to improve inorganic photochromic materials is usually to modify the nano-powder with a silane coupling agent. The improvement mechanism is that the coupling agent hydrolyzes to form silanol, and then undergoes a dehydration condensation reaction with the hydroxyl groups on the surface of the nanoparticles to graft onto the particle surface. However, in this process, the coupling agent is prone to self-condensation reaction, resulting in poor dispersion performance, limited improvement effect, and still room for improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide a photochromic glass to solve the problems in the background art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A photochromic glass, comprising a first glass layer, an organic-inorganic composite layer, and a second glass layer arranged in sequence from top to bottom;

[0007] This photochromic glass is made through the following steps:

[0008] Stack the first glass, the organic-inorganic composite film material, and the second glass in sequence, put them into a silica gel bag, evacuate for 20 minutes under a vacuum degree of 2.5 KPa, transfer to a drying furnace and keep warm at 85 °C for 30 minutes, then in an autoclave, at a temperature of 110 - 150 °C and a pressure of 1 - 3 MPa, hot press for 25 minutes, and then cool to room temperature to obtain the photochromic glass.

[0009] Further, the organic-inorganic composite film material is made through the following steps:

[0010] Prepare the following raw materials by mass percentage: 0.5 - 2% photochromic powder, 0.5 - 1% functional material, 20 - 30% plasticizer, and the balance is polyvinyl butyral. Add the above raw materials into a kneader and stir for 10 - 20 min, then heat to 140 - 160 °C for melt extrusion to make a film with a thickness of 0.5 - 1.2 mm. After operations such as cooling, dewatering, and drying, an organic-inorganic composite film material is obtained.

[0011] Furthermore, the functional material is prepared through the following steps:

[0012] Step S1: Add nano cesium tungsten bronze powder into absolute ethanol, ball mill for 3 h, then add an alcohol solution for activating polyvinyl butyral to the ball mill liquid, continue to stir for 1 h, ultrasonicate for 30 - 40 min, centrifuge, and dry the precipitate to obtain modified nano cesium tungsten bronze;

[0013] Among them, the dosage ratio of nano cesium tungsten bronze powder, absolute ethanol, and the alcohol solution for activating polyvinyl butyral is 10 g : 90 - 110 mL : 10 mL, and the alcohol solution for activating polyvinyl butyral is composed of activating polyvinyl butyral and absolute ethanol according to 0.4 g : 10 mL;

[0014] Step S2: Disperse the modified nano cesium tungsten bronze in DMF, add an auxiliary agent, allyl succinic anhydride, and benzoyl peroxide, stir and react at 75 - 80 °C for 3 - 5 h. After the reaction, perform suction filtration, wash the filter cake with absolute ethanol 3 - 5 times, and dry to obtain the functional material;

[0015] Among them, the dosage ratio of modified nano cesium tungsten bronze, DMF, auxiliary agent, allyl succinic anhydride, and benzoyl peroxide is 10 g : 100 mL : 0.2 - 0.3 g : 0.4 - 0.6 g : 0.03 - 0.05 g.

[0016] Cesium tungsten bronze nano powder has strong absorption in the near-infrared region (wavelength 800 - 1200 nm) and high transmittance in the visible light region (wavelength 380 - 780 nm). When it is applied to photochromic glass, it can endow the photochromic glass with good optical properties.

[0017] In order to improve the dispersibility of cesium tungsten bronze nano powder in the organic film matrix (polyvinyl butyral), the present invention conducts modification treatment on it, which is divided into two steps:

[0018] First, the nano cesium tungsten bronze powder is evenly dispersed in absolute ethanol through ball milling treatment, and then coated with activated polyvinyl butyral. When the activated polyvinyl butyral is coated on the surface of the cesium tungsten bronze nano powder, it generates an electrostatic stabilization effect and a steric hindrance effect, improving the dispersibility of the nano cesium tungsten bronze powder in polyvinyl butyral. Compared with directly coating with polyvinyl butyrate, the combination of the activated polyvinyl butyral and the nano cesium tungsten bronze powder is closer. The reason is that the introduction of carboxyl groups in the activated polyvinyl butyral molecules improves the hydrogen bond interaction between the activated polyvinyl butyral and the nano cesium tungsten bronze powder, enabling the activated polyvinyl butyral to be evenly coated on the surface of the nano cesium tungsten bronze powder;

[0019] Then, the present invention uses allyl succinic anhydride and an auxiliary agent to react with the unsaturated double bonds in the activated polyvinyl butyric acid molecules, grafting active anhydride groups, hindered amine structures, and thiourea structures on the surface of the modified nano cesium tungsten bronze molecules to obtain a functional material.

[0020] Furthermore, the activated polyvinyl butyral is prepared through the following steps:

[0021] Add polyvinyl butyral, p-toluenesulfonic acid, and DMF into a flask, stir and dissolve them, then add maleic anhydride, heat up to 55 - 60 °C, stir and react for 5 - 6 h. After the reaction ends, cool to room temperature, add acetone, continue to stir for 30 min, then transfer to distilled water, stir and filter. The filter cake is washed with deionized water multiple times and dried to obtain the activated polyvinyl butyral;

[0022] Among them, the dosage ratio of polyvinyl butyral, p-toluenesulfonic acid, DMF, and maleic anhydride is 6 g : 0.18 - 0.25 g : 100 mL : 3 g. Under the catalytic action of p-toluenesulfonic acid, the hydroxyl groups in the polyvinyl butyral molecular chain undergo a ring-opening reaction with maleic anhydride, introducing active carboxyl groups and unsaturated double bonds to obtain the activated polyvinyl butyral.

[0023] Furthermore, the auxiliary agent is prepared through the following steps:

[0024] At room temperature, add 4-amino-1,2,2,6,6-pentamethylpiperidine and 1,4-dioxane into a three-necked flask, stir and dissolve them, then add dibutyltin dilaurate, and then dropwise add allyl isothiocyanate while stirring. After the dropping ends, heat up to 50 °C, stir and react for 4 - 6 h. After the reaction ends, rotary evaporate to remove 1,4-dioxane to obtain the auxiliary agent;

[0025] Among them, the dosage ratio of 4-amino-1,2,2,6,6-pentamethylpiperidine, 1,4-dioxane, dibutyltin dilaurate and allyl isothiocyanate is 60 mmol: 60 mL: 0.058 - 0.062 g: 70 - 72 mmol. Using 4-amino-1,2,2,6,6-pentamethylpiperidine and allyl isothiocyanate as raw materials, through the reaction of amino group and isothiocyanato group, an auxiliary agent containing a hindered amine structure, a thiourea structure and an unsaturated double bond is obtained.

[0026] Further, the photochromic powder is 1,2-dihydro-5-hydroxynaphthocyclopent-3-one.

[0027] Further, the plasticizer is one or more of triethylene glycol diisooctanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol diisooctanoate, dibutyl sebacate, dihexyl adipate, dipentaerythritol ester, mixed in any proportion.

[0028] Further, the thickness of the first glass and the second glass is 1.6 - 3.0 mm, selected from ordinary float glass or ultra-clear float glass.

[0029] Advantages of the present invention:

[0030] 1. The present invention selects a photochromic powder with fast light response and anti-fatigue properties as the basic photochromic material, selects cesium tungsten bronze nanoparticles with spectral selective absorption as the near-infrared light shielding material, and selects polyvinyl butyral as the main film carrier material. Using ultrasonic dispersion and high-speed ball milling equipment, cesium tungsten bronze nanoparticles are made into functional materials; then polyvinyl butyral plasticizer, as well as organic photochromic powder and functional materials are added to a mixer and stirred and mixed together, and then extruded into a film by heating with a casting machine to obtain a functional layer composite film; then it is made into photochromic glass, which has good weather resistance and color change response speed.

[0031] 2. The present invention makes cesium tungsten bronze nanoparticles into functional materials, and utilizes the hydrogen bond interaction between activated polyvinyl butyral and nano-cesium tungsten bronze powder to uniformly coat the surface of nano-cesium tungsten bronze powder with activated polyvinyl butyral, generating an electrostatic stabilization effect and a steric hindrance effect, improving the dispersibility of nano-cesium tungsten bronze powder in polyvinyl butyral. Compared with directly using a silane coupling agent for treatment, the dispersibility is high, and the obtained photochromic glass has a low haze and good optical properties.

[0032] 3. The present invention introduces allyl succinic anhydride and an auxiliary agent onto the surface of modified nano cesium tungsten bronze by means of chemical grafting, that is, introducing active anhydride groups, hindered amine structures, and thiourea structures onto the surface of modified nano cesium tungsten bronze. The anhydride groups can react with active hydroxyl groups, improving the stability of nano cesium tungsten bronze in the film matrix and enhancing the adhesion between the organic-inorganic composite film and the glass substrate. The introduction of the hindered amine structure can improve the light resistance of the organic-inorganic composite film, and the thiourea structure can improve the antioxidant performance of the organic-inorganic composite film. Therefore, the preparation and addition of the functional material can endow the photochromic glass with excellent optical properties and weather resistance. Detailed implementation manners

[0033] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0034] Example 1

[0035] The auxiliary agent is prepared through the following steps:

[0036] At room temperature, 60 mmol of 4-amino-1,2,2,6,6-pentamethylpiperidine and 60 mL of 1,4-dioxane are added to a three-necked flask. After stirring and dissolving, 0.058 g of dibutyltin dilaurate is added. Then, while stirring, 70 mmol of allyl isothiocyanate is added dropwise. After the addition is completed, the temperature is raised to 50 °C and the reaction is stirred for 4 h. After the reaction is completed, 1,4-dioxane is removed by rotary evaporation to obtain the auxiliary agent.

[0037] Example 2

[0038] The auxiliary agent is prepared through the following steps:

[0039] At room temperature, 60 mmol of 4-amino-1,2,2,6,6-pentamethylpiperidine and 60 mL of 1,4-dioxane are added to a three-necked flask. After stirring and dissolving, 0.062 g of dibutyltin dilaurate is added. Then, while stirring, 72 mmol of allyl isothiocyanate is added dropwise. After the addition is completed, the temperature is raised to 50 °C and the reaction is stirred for 6 h. After the reaction is completed, 1,4-dioxane is removed by rotary evaporation to obtain the auxiliary agent.

[0040] Example 3

[0041] The functional material is prepared through the following steps:

[0042] Step S1: Add 10 g of nano cesium tungsten bronze powder into 90 mL of absolute ethanol, ball mill for 3 h, then add the alcohol solution of activated polyvinyl butyral into the ball milled solution, continue stirring for 1 h, ultrasonicate for 30 min, centrifuge, and dry the precipitate to obtain modified nano cesium tungsten bronze. The alcohol solution of activated polyvinyl butyral is composed of activated polyvinyl butyral and absolute ethanol in a ratio of 0.4 g:10 mL.

[0043] Step S2: Disperse 10 g of modified nano cesium tungsten bronze in 100 mL of DMF, add 0.2 g of auxiliary agent, 0.4 g of allyl succinic anhydride and 0.03 g of benzoyl peroxide, stir and react at 75 °C for 3 h. After the reaction, filter by suction, wash the filter cake with absolute ethanol three times, and dry to obtain the functional material.

[0044] Activated polyvinyl butyral is prepared through the following steps:

[0045] Add 6 g of polyvinyl butyral, 0.18 g of p-toluenesulfonic acid and 100 mL of DMF into a flask, stir and dissolve, then add 3 g of maleic anhydride, raise the temperature to 55 °C, stir and react for 5 h. After the reaction, cool to room temperature, add acetone, continue stirring for 30 min, then transfer to distilled water, stir and filter by suction. Wash the filter cake with deionized water for multiple times and dry to obtain activated polyvinyl butyral.

[0046] Example 4

[0047] The functional material is prepared through the following steps:

[0048] Step S1: Add 10 g of nano cesium tungsten bronze powder into 110 mL of absolute ethanol, ball mill for 3 h, then add the alcohol solution of activated polyvinyl butyral into the ball milled solution, continue stirring for 1 h, ultrasonicate for 40 min, centrifuge, and dry the precipitate to obtain modified nano cesium tungsten bronze. The alcohol solution of activated polyvinyl butyral is composed of activated polyvinyl butyral and absolute ethanol in a ratio of 0.4 g:10 mL.

[0049] Step S2: Disperse 10 g of modified nano cesium tungsten bronze in 100 mL of DMF, add 0.3 g of auxiliary agent, 0.6 g of allyl succinic anhydride and 0.05 g of benzoyl peroxide, stir and react at 80 °C for 5 h. After the reaction, filter by suction, wash the filter cake with absolute ethanol five times, and dry to obtain the functional material.

[0050] Activated polyvinyl butyral is prepared through the following steps:

[0051] 6 g of polyvinyl butyral, 0.25 g of p-toluenesulfonic acid and 100 mL of DMF were added to a flask. After stirring and dissolving, 3 g of maleic anhydride was added. The temperature was raised to 60 °C and stirred for 6 h. After the reaction, it was cooled to room temperature, acetone was added, and stirring was continued for 30 min. Then it was transferred to distilled water, stirred and filtered by suction. The filter cake was washed with deionized water several times and dried to obtain activated polyvinyl butyral.

[0052] Comparative Example 1

[0053] This comparative example provides a functional material:

[0054] Step S1: 10 g of nano cesium tungsten bronze powder was added to 110 mL of 50 wt% absolute ethanol and ball milled for 3 h. Then, an alcohol solution of KH-570 was added to the ball milling solution, and stirring was continued for 1 h, followed by ultrasonic treatment for 40 min. After centrifugation, the precipitate was dried to obtain modified nano cesium tungsten bronze. The alcohol solution of activated polyvinyl butyral was composed of KH-570 and absolute ethanol in a ratio of 0.4 g:10 mL.

[0055] Comparative Example 2

[0056] This comparative example was the modified nano cesium tungsten bronze obtained in Step S1 of Example 3.

[0057] Example 5

[0058] A photochromic glass, comprising a first glass layer, an organic-inorganic composite layer and a second glass layer arranged in sequence from top to bottom;

[0059] This photochromic glass was made through the following steps:

[0060] The first glass, the organic-inorganic composite film material and the second glass were stacked in sequence and then placed in a silica gel bag. The air was evacuated at a vacuum degree of 2.5 KPa for 20 min and then transferred to a drying furnace for heat preservation at 85 °C for 30 min. Then, in an autoclave, at a temperature of 110 °C and a pressure of 3 MPa, hot pressing was carried out for 25 min. After that, it was cooled to room temperature to obtain the photochromic glass.

[0061] Among them, the organic-inorganic composite film material was made through the following steps:

[0062] Prepare the following raw materials in mass percentages: 0.5% of 1,2-dihydro-5-hydroxynaphthacene-3-one, 0.5% of the functional material of Example 3, 20% of triethylene glycol diisooctanoate, and the balance was polyvinyl butyral. The above raw materials were added to a mixer and stirred for 10 min. Then it was heated to 140 °C for melt extrusion and made into a 0.5 mm film. After operations such as cooling, water removal, and air drying, the organic-inorganic composite film material was obtained.

[0063] The thicknesses of the first glass and the second glass were 1.6 mm, and they were selected from ordinary float glass.

[0064] Example 6

[0065] A photochromic glass, comprising a first glass layer, an organic-inorganic composite layer, and a second glass layer sequentially arranged from top to bottom;

[0066] This photochromic glass is made through the following steps:

[0067] Stack the first glass, the organic-inorganic composite film material, and the second glass in sequence, then put them into a silica gel bag, evacuate for 20 min under a vacuum of 2.5 KPa, transfer to a drying furnace and keep warm at 85 °C for 30 min, then in an autoclave, at a temperature of 120 °C and a pressure of 2 MPa, hot press for 25 min, and then cool to room temperature to obtain the photochromic glass.

[0068] Among them, the organic-inorganic composite film material is made through the following steps:

[0069] Prepare the following raw materials by mass percentage: 1% 1,2-dihydro-5-hydroxynaphthocyclopent-3-one, 0.8% of the functional material in Example 4, 25% triethylene glycol di-n-heptanoate, and the balance is polyvinyl butyral. Add the above raw materials into a mixer and stir for 15 min, then heat to 150 °C, melt and extrude to make a 1.0 mm film, and then through operations such as cooling, dewatering, and air drying, the organic-inorganic composite film material is obtained.

[0070] Among them, the thickness of the first glass and the second glass is 2.0 mm, and they are selected from ordinary float glass.

[0071] Example 7

[0072] A photochromic glass, comprising a first glass layer, an organic-inorganic composite layer, and a second glass layer sequentially arranged from top to bottom;

[0073] This photochromic glass is made through the following steps:

[0074] Stack the first glass, the organic-inorganic composite film material, and the second glass in sequence, then put them into a silica gel bag, evacuate for 20 min under a vacuum of 2.5 KPa, transfer to a drying furnace and keep warm at 85 °C for 30 min, then in an autoclave, at a temperature of 150 °C and a pressure of 1 MPa, hot press for 25 min, and then cool to room temperature to obtain the photochromic glass.

[0075] Among them, the organic-inorganic composite film material is made through the following steps:

[0076] Prepare the following raw materials by mass percentage: 2% of 1,2-dihydro-5-hydroxynaphthocyclopent-3-one, 1% of the functional material of Example 3, 30% of tetraethylene glycol diisooctanoate, and the balance is polyvinyl butyral. Add the above raw materials into a mixer and stir for 20 min, then heat to 160 °C for melt extrusion to make a 1.2-mm film. After operations such as cooling, dewatering, and air drying, an organic-inorganic composite film material is obtained.

[0077] Among them, the thicknesses of the first glass and the second glass are 3.0 mm, and they are selected from ordinary float glass.

[0078] Comparative Example 3

[0079] Compared with Example 5, the functional material in Example 5 was replaced with the substance in Comparative Example 1, and the remaining raw materials and preparation process were the same as those in Example 5.

[0080] Comparative Example 4

[0081] Compared with Example 5, the functional material in Example 5 was replaced with the substance in Comparative Example 2, and the remaining raw materials and preparation process were the same as those in Example 5.

[0082] Perform performance tests on the photochromic glasses obtained in Examples 5 to 7 and Comparative Examples 3 to 4. The test contents are as follows:

[0083] Weather resistance: According to Standards GB / T5137.3-2002 and GB15763.3-2009, place the prepared photochromic glass in an environment of 50 °C and 90% relative humidity for 7 days, and then observe whether the edge part of the photochromic glass turns yellow;

[0084] Discoloration response speed test: Irradiate the prepared photochromic glass under the same light, and then measure the time required for the photochromic glass to reach the color development temperature state as the color development response time (unit: second).

[0085] Transmittance / haze test: Test the transmittance, haze, and bonding strength of the photochromic glass according to Standard GB / T2680-1994;

[0086] The results are shown in Table 1:

[0087] Table 1

[0088] Project Example 5 Example 6 Example 7 Comparative Example 3 Comparative Example 4 Weather resistance No yellowing No yellowing No yellowing Yellowing Yellowing Color display response time (s) 20 17 15 22 21 Transmittance (%) 89.4 91.6 92.3 85.6 88.6 Haze (%) 0.57 0.48 0.45 0.74 0.59 Adhesion strength (grade) Grade 5 Grade 5 Grade 5 Grade 4.5 Grade 4.5

[0089] As can be seen from Table 1, compared with Comparative Examples 3 to 4, the photochromic glasses prepared in Examples 5 to 7 not only have high weather resistance but also good optical properties.

[0090] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0091] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A photochromic glass, characterized in that, it comprises a first glass layer, an organic-inorganic composite layer and a second glass layer which are arranged in sequence from top to bottom, and the organic-inorganic composite layer is obtained from an organic-inorganic composite film material; The organic-inorganic composite film material is prepared by the following steps: Prepare the following raw materials by mass percentage: 0.5-2% photochromic powder, 0.5-1% functional material, 20-30% plasticizer, and the balance is polyvinyl butyral. Add the above raw materials to the mixing and kneading, and then heat to 140-160°C for melting and extrusion to make a film, obtaining the organic-inorganic composite film material; The functional material is prepared by the following steps: Step S1: Add nano-cesium tungsten bronze powder to absolute ethanol, ball mill for 3 h, then add an alcohol solution of activated polyvinyl butyral to the ball mill liquid, continue stirring for 1 h, ultrasonicate for 30-40 min, centrifuge, and dry the precipitate to obtain modified nano-cesium tungsten bronze; Step S2: Disperse the modified nano-cesium tungsten bronze in DMF, add an auxiliary agent, allyl succinic anhydride and benzoyl peroxide, and stir and react at 75-80°C for 3-5 h to obtain the functional material; The activated polyvinyl butyral is prepared by the following steps: Mix polyvinyl butyral, p-toluenesulfonic acid and DMF, stir and dissolve, then add maleic anhydride, raise the temperature to 55-60°C, and stir and react for 5-6 h to obtain the activated polyvinyl butyral.

2. The photochromic glass according to claim 1, characterized in that, the alcohol solution of activated polyvinyl butyral is composed of activated polyvinyl butyral and absolute ethanol at a ratio of 0.4 g: 10 mL.

3. The photochromic glass according to claim 1, characterized in that, the dosage ratio of the modified nano-cesium tungsten bronze, DMF, auxiliary agent, allyl succinic anhydride and benzoyl peroxide is 10 g: 100 mL: 0.2-0.3 g: 0.4-0.6 g: 0.03-0.05 g.

4. The photochromic glass according to claim 1, characterized in that, the dosage ratio of polyvinyl butyral, p-toluenesulfonic acid, DMF and maleic anhydride is 6 g: 0.18-0.25 g: 100 mL: 3 g.

5. The photochromic glass according to claim 1, characterized in that, the auxiliary agent is prepared by the following steps: Mix 4-amino-1,2,2,6,6-pentamethylpiperidine and 1,4-dioxane, add dibutyltin dilaurate, dropwise add allyl isothiocyanate while stirring, after the dropping is completed, raise the temperature to 50°C, and stir and react for 4-6 h to obtain the auxiliary agent.

6. The photochromic glass according to claim 5, characterized in that, the dosage ratio of 4-amino-1,2,2,6,6-pentamethylpiperidine, 1,4-dioxane, dibutyltin dilaurate and allyl isothiocyanate is 60 mmol: 60 mL: 0.058-0.062 g: 70-72 mmol.