Photochromic polyamide materials and precursors thereof, methods of preparation, photoinitiators and applications

Abstract

Photochromic polyamide materials, their precursors, preparation methods, photoinitiators, and applications are disclosed. The precursors for photochromic materials are described, which are used to prepare photochromic polyamide materials. This process involves mixing the precursor with multifunctional hydrocarbon groups or their derivatives to obtain the photochromic material. Specific functional hydrocarbon groups can be selected for mixing to enhance the performance of the photochromic material. By introducing photochromic units into the polyamide structure, the material can quickly respond to ultraviolet light and return to a colorless state, maintaining excellent photochromic effects. Simultaneously, the polyamide matrix significantly enhances the material's mechanical strength, wear resistance, and environmental adaptability, giving it long-term stable color-changing properties. This makes it suitable for various fields such as smart coatings and optical devices. This solution addresses the technical problems of existing naphthol-pyran-based photochromic materials in terms of photoresponse, mechanical properties, and chemical stability.

Description

Technical Field

[0001] This invention relates to the field of photochromic materials, and more particularly to a photochromic polyamide material, its precursor, preparation method, photoinitiator, and applications. Background Technology

[0002] Photochromic materials are a class of functional materials that change color under ultraviolet light irradiation and are widely used in smart coatings, sensors, and optical devices. Typical photochromic molecules, such as naphthol-pyran compounds, undergo conformational changes under ultraviolet light irradiation through heterolytic cleavage of the CO bonds, causing the molecules to change from a colorless state to a colored state. When the ultraviolet light is removed or heating is applied, the molecules reclose their rings, returning to a colorless state. This reversible ring-opening and ring-closing reaction makes naphthol-pyran photochromic molecules highly promising for applications in smart coatings.

[0003] However, existing photochromic materials still face numerous challenges in practical applications. For instance, existing naphthol-pyran compounds often exhibit a gradual weakening of their photochromic response after repeated use, with prolonged light response times and insufficient depth of color change. Furthermore, existing photochromic materials suffer from insufficient mechanical properties, typically failing to maintain long-term wear resistance and stability during application, especially in dynamic environments or scenarios with significant mechanical wear, where their photochromic performance is prone to degradation. Weather resistance is also a major challenge; the color-changing ability of existing materials easily decreases or even completely fails under humid, ultraviolet-exposed, and acidic / alkaline conditions. Particularly in outdoor environments, photochromic materials require extremely high weather resistance and anti-aging properties, which are difficult to achieve with current technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a precursor for photochromic polyamide materials, which can be used to prepare photochromic polyamide materials. The photochromic materials can be prepared by simply mixing the precursor with multifunctional hydrocarbon groups or their derivatives. Specific hydrocarbon groups with specific functions can be selected for mixing as needed to enhance the performance of the photochromic materials.

[0005] The present invention also proposes a photochromic polyamide material.

[0006] To achieve this objective, the present invention adopts the following technical solution: A precursor to a photochromic material, with the following molecular formula: ; Where G is the active functional group; m is a natural number, m≥0; and n is the degree of polymerization.

[0007] Optimally, G can be a hydroxyl, carboxyl, aldehyde, carbonyl, amino, nitro, halogen, alkynyl, epoxy, or isocyanate group.

[0008] A method for preparing a precursor of a photochromic material includes the following steps: S1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; S2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; S3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; S5: Dissolve intermediate A-7 in acid, and slowly add sodium nitrite solution at 0-5℃ to generate a diazonium salt; after the reaction is complete, add ice water and stir; add excess water, filter the product, collect the product, and wash with water until neutral to obtain intermediate A-8; intermediate A-8 is... ; S6: Add solvent to intermediate A-8 and dissolve it under stirring. Add bromoalkane derivative A-9 and triethylamine and stir to react. After the reaction is complete, wash the organic phase with water, separate the organic layer, dry and purify to obtain the precursor A-111 of the photochromic material. Bromoalkyl derivative A-9 is The proto-body A-111 is: G is the active functional group, and m is a natural number.

[0009] Alternatively, in step S6, intermediate A-8 is dissolved in solvent by stirring, and bromine-containing alkyl derivative A-9 with Boc anhydride protecting the active functional group G and triethylamine are added and stirred to react. After the reaction is complete, the organic phase is washed with water, the organic layer is separated, dried and purified to obtain compound A-10. A-9, a bromoalkylamine derivative, is Intermediate A-10 is ; After step S6, continue to step S7; S7: Dissolve intermediate A-10 in a solvent, add trifluoroacetic acid, remove the Boc protecting group, and generate the precursor A-111 of the photochromic material.

[0010] A photochromic polyamide material, the molecular structure of which is: ; Wherein, R is a hydrocarbon group or a derivative of a hydrocarbon group; m is a natural number, m≥0; n is the degree of aggregation.

[0011] Ideally, the molecular structure can be one of the following substructures: .

[0012] A method for preparing a photochromic polyamide material includes the following steps: Will The dicarboxylic acid monomer is added to a solvent, a dehydrating agent and a catalyst are added, and the reaction is carried out under a protective atmosphere to promote the polymerization of amino and carboxyl groups. After the reaction, the mixture is purified to obtain... ; The molecular structure of a dicarboxylic acid monomer is HOOC-R-COOH; R is a hydrocarbon group or a derivative of a hydrocarbon group.

[0013] A photoinitiator, comprising: a photochromic polyamide material; The photochromic polyamide material is one of the above-mentioned photochromic polyamide materials, or it is prepared by the above-mentioned method for preparing a photochromic polyamide material.

[0014] An application of a polymer in optical devices, wherein the polymer is the aforementioned photochromic polyamide material, or is prepared by the aforementioned method for preparing a photochromic polyamide material.

[0015] The application of a polymer in the preparation of smart coatings, wherein the polymer is the above-mentioned photochromic polyamide material, or is prepared by the above-mentioned method for preparing a photochromic polyamide material.

[0016] Compared with the prior art, one of the above technical solutions has the following beneficial effects: 1. This solution provides a precursor for photochromic polyamide materials, which is used to prepare photochromic polyamide materials. The photochromic material can be obtained by simply mixing the precursor with a multifunctional hydrocarbon group or its derivative. Specific hydrocarbon groups with specific functions can be selected for mixing to enhance the performance of the photochromic material. This solves the problem that existing materials cannot simultaneously achieve good photoresponse performance, thermal stability, mechanical properties, and weather resistance.

[0017] 2. This invention introduces photochromic units into the polyamide structure, enabling the material to respond rapidly and return to a colorless state under ultraviolet light irradiation, maintaining excellent photochromic effects. Simultaneously, the polyamide matrix significantly enhances the material's mechanical strength, wear resistance, and environmental adaptability, giving it long-term stable color-changing properties. This makes it suitable for various fields such as smart coatings and optical devices, solving the technical problems of existing naphthol-pyran-based photochromic materials in terms of photoresponse, mechanical properties, and chemical stability. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more comprehensive description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0019] A precursor to a photochromic material, with the following molecular formula: ; Where G is the active functional group; m is a natural number, m≥0; and n is the degree of polymerization.

[0020] This solution provides a precursor for photochromic polyamide materials, which is used to prepare photochromic polyamide materials. The photochromic material can be obtained simply by mixing the precursor with a multifunctional hydrocarbon group or its derivative. Specific hydrocarbon groups with specific functions can be selected for mixing to enhance the performance of the photochromic material. This solves the problem that existing materials cannot simultaneously achieve good photoresponse performance, thermal stability, mechanical properties, and weather resistance.

[0021] Wherein, G is an active functional group, which can be one of the following: hydroxyl (-OH), carboxyl (-COOH), aldehyde (-CHO), carbonyl, amino (-NH2), nitro (-NO2), halogen group, alkynyl, epoxy group, or isocyanate group (-NCO). The precursor contains two active functional groups G. When the precursor reacts with the G1-R-G1 monomer (G1 is an active functional group that can polymerize with G), the G of the precursor and the G1 of G1-R-G1 undergo a polymerization reaction. The precursor reacts with -R- to form a polymer. -R- can have a functional group with certain functions, such as excellent mechanical properties, weather resistance, and chemical stability. When the precursor reacts with the G1-R-G1 monomer, it can enhance the performance of the precursor, thereby achieving both photoresponse performance and mechanical properties.

[0022] In one embodiment, G is a hydroxyl group and G1 may be a carboxyl group; in one embodiment, G is a hydroxyl group and G1 may be an amino group; in one embodiment, G is an isocyanate group and G1 may be a hydroxyl group, and vice versa.

[0023] Optimally, G can be a hydroxyl, carboxyl, aldehyde, carbonyl, amino, nitro, halogen, alkynyl, epoxy, or isocyanate group.

[0024] The solvent used in this invention refers to any solvent capable of dissolving the reactants. The role of the solvent is to achieve a uniform molecular dispersion of the reactants, i.e., the dissolution process. The dissolution process includes two steps: the diffusion (endothermic) of solute molecules (or ions) and the interaction with solvent molecules to form solvated molecules (exothermic). Based on the principle of "dissolving what resembles," polar solvents are suitable for dissolving polar compounds, and nonpolar solvents are suitable for dissolving nonpolar compounds. Those skilled in the art can select an appropriate solvent based on the polarity characteristics of the reactants.

[0025] A method for preparing a precursor of a photochromic material includes the following steps: S1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; The solvent for this step can be selected from one or a combination of anhydrous toluene, xylene, petroleum ether, n-hexane, etc. The molar ratio of compound A-1 to compound A-2 can be 1:(0.1-10), for example 1:1, 1:1.05, 1:1.1, 1:2, etc.

[0026] S2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; The solvent used in this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. The molar ratio of compound A-3 to compound A-4 can be 1:(0.1-10), for example 1:1, 1:1.05, 1:1.1, 1:2, etc.

[0027] S3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; The solvent for this step can be selected from one or a combination of ethanol, methanol, butanol, n-propanol, isopropanol, ethylene glycol, acetone, and diethyl ether. The reducing agent can be selected from elemental metals such as magnesium (Mg), aluminum (Al), zinc (Zn), and iron (Fe).

[0028] S5: Dissolve intermediate A-7 in acid, and slowly add sodium nitrite solution at 0-5℃ to generate a diazonium salt; after the reaction is complete, add ice water and stir; add excess water, filter the product, collect the product, and wash with water until neutral to obtain intermediate A-8; intermediate A-8 is... ; The acid used in this step can be an acidic solution such as hydrochloric acid or sulfuric acid.

[0029] The reaction formulas for steps S1 to S5 are as follows: ; S6: Add solvent to intermediate A-8 and dissolve it under stirring. Add bromoalkane derivative A-9 and triethylamine and stir to react. After the reaction is complete, wash the organic phase with water, separate the organic layer, dry and purify to obtain the precursor A-111 of the photochromic material. Bromoalkyl derivative A-9 is The proto-body A-111 is: G is the active functional group, and m is a natural number.

[0030] The solvent used in this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. In this embodiment, the molar ratio of compound A-8 to compound A-9 can be 1:(0.1-10), for example, 1:1, 1:2, 1:2.1, 1:2.2, etc.

[0031] The bromoalkylamine derivative A-9 in this step uses an active functional group G that does not require protection with Boc anhydride. In this embodiment, the active functional group G can be a monovalent functional group, such as hydroxyl (-OH), carboxyl (-COOH), aldehyde (-CHO), amino (-NH2), etc.

[0032] The reaction formula for this embodiment is: ; Alternatively, in step S6, intermediate A-8 is dissolved in solvent by stirring, and bromine-containing alkyl derivative A-9 with Boc anhydride protecting the active functional group G and triethylamine are added and stirred to react. After the reaction is complete, the organic phase is washed with water, the organic layer is separated, dried and purified to obtain compound A-10. A-9, a bromoalkylamine derivative, is Intermediate A-10 is ; The bromoalkylamine derivative A-9 in this step uses Boc anhydride to protect the active functional group G. In this example, the active functional group G is a divalent functional group, such as ether bond (-O-), carbonyl (-CO-), imino (-NH-), etc.

[0033] The solvent used in this step can be selected from one or a combination of ethanol, methanol, butanol, n-propanol, isopropanol, ethylene glycol, acetone, diethyl ether, etc. In this embodiment, the molar ratio of compound A-8 to compound A-9 can be 1:(0.1-10), for example, 1:1, 1:2, 1:2.1, 1:2.2, etc.

[0034] After step S6, continue to step S7; S7: Dissolve intermediate A-10 in a solvent, add trifluoroacetic acid, remove the Boc protecting group, and generate the precursor A-111 of the photochromic material.

[0035] The solvent for this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc. The molar ratio of intermediate A-10 to trifluoroacetic acid can be 1:(0.1-10), for example 1:1, 1:2, 1:2.1, 1:2.2, etc.

[0036] The reaction formula for this embodiment is: .

[0037] A photochromic polyamide material, the molecular structure of which is: ; Where R is a hydrocarbon group or a hydrocarbon derivative; m is a natural number, m≥0; and n is the degree of polymerization.

[0038] This solution provides a photochromic polyamide material, which is a novel material prepared by introducing photochromic units into the polyamide structure. Through this molecular structure design, the material has achieved significant improvements in photochromic performance, mechanical strength, chemical stability and application adaptability, and solves the problem that existing materials cannot simultaneously achieve photoresponse performance, thermal stability, mechanical properties and weather resistance.

[0039] To improve the photochromic performance, this solution optimizes the molecular structure to ensure that the material maintains a fast and stable photoresponse performance after multiple light-color-change cycles. At the same time, the material changes color rapidly under ultraviolet light and can quickly return to a colorless state under heating or visible light, exhibiting excellent photoresponse speed and repeatability.

[0040] Regarding the enhancement of mechanical properties, this solution introduces photochromic units into the polyamide matrix, resulting in a significant improvement in the material's mechanical properties, exhibiting excellent tensile strength, abrasion resistance, and adhesion. This enables the material to maintain its functional integrity over a long period in coating applications, resisting physical friction and mechanical stress, making it particularly suitable for scenarios with high coating performance requirements, such as vehicle coatings and building exterior wall coatings.

[0041] To enhance weather resistance and chemical stability, this solution introduces a polyamide structure, significantly improving the material's weather resistance in harsh environments. Under conditions of high temperature, humidity, and acid / alkali, the material maintains good photochromic properties and exhibits excellent chemical stability. Its resistance to UV aging is further improved, enabling its widespread application in smart materials and devices for outdoor conditions.

[0042] In summary, by combining the precursor of the photochromic material with the polyamide matrix, this invention not only overcomes the problems of unstable photoresponse performance, poor mechanical properties, and insufficient environmental adaptability of existing materials, but also significantly enhances their application potential in fields such as smart coatings, optics, and sensors, providing a brand-new technical solution for the future development of smart materials.

[0043] In one embodiment, m is a natural number, which can be 0, i.e., the corresponding alkyl group does not exist; m can also be >0, for example 10, 20, 30, 40...; -R- represents one of the following: alkyl, alkyl derivative, aryl, aryl derivative, benzyl, or benzyl derivative. Examples of alkyl groups include: methylene (-CH2-), ethylene (-CH2CH2-), 1,3-propylene (-CH2CH2CH2-), 1,4-butylene (-CH2CH2CH2CH2-), 1,2-propylene (-CH2CH(CH3)-), and 1,1-propylene (-C(CH3)2-). Examples of alkyl derivatives include: 1,2-dichloroethane (ClCH2CH2Cl), and 1,3-dibromopropane (BrCH2CH2CH2B). r), 1,4-dichlorobutane (ClCH2CH2CH2CH2Cl), 1,2-dibromoethane (BrCH2CH2Br), 1,3-dichloropropane (ClCH2CH2CH2Cl), 1,4-dibromobutane (BrCH2CH2CH2CH2Br); aryl groups such as: 1,2-phenylene (-C6H4-), 1,3-phenylene (-C6H4-), 1,4-phenylene (-C6H4-), 1,2-naphthylene (-C 10 H6-, naphthalene ring at 1,2 positions), 1,4-naphthylene (-C) 10 H6-, naphthalene ring 1,4 position), 1,5-naphthylene (-C) 10 H6- (naphthalene ring at positions 1 and 5); aryl derivatives such as aryl with halogen atoms or other substituents. Benzyl derivatives such as benzyl with halogen atoms or other substituents.

[0044] Ideally, the molecular structure can be one of the following substructures: .

[0045] A method for preparing a photochromic polyamide material includes the following steps: Will The dicarboxylic acid monomer is added to a solvent, a dehydrating agent and a catalyst are added, and the reaction is carried out under a protective atmosphere to promote the polymerization of amino and carboxyl groups. After the reaction, the mixture is purified to obtain... ; The molecular structure of a dicarboxylic acid monomer is HOOC-R-COOH; R is a hydrocarbon group or a derivative of a hydrocarbon group.

[0046] The solvent for this step can be selected from one or a combination of halogenated hydrocarbon solvents (anhydrous dichloromethane, chloroform, anhydrous dichloroethane, dichloropropane, etc.), N-methylpyrrolidone, ethylene glycol ether solvents, ester solvents, etc.

[0047] The dehydrating agent is a known glue agent used in organic reactions, such as DCC or EDC; the catalyst has catalytic activity and a specific catalyst can be selected according to the specific reaction requirements, for example, DMAP can be used in the reaction of amino and carboxyl groups. The protective gas is an inert gas, such as nitrogen, helium, argon, etc.

[0048] The reaction formula for this step is: .

[0049] A photoinitiator, comprising: a photochromic polyamide material; The photochromic polyamide material is one of the above-mentioned photochromic polyamide materials, or it is prepared by the above-mentioned method for preparing a photochromic polyamide material.

[0050] An application of a polymer in optical devices, wherein the polymer is the aforementioned photochromic polyamide material, or is prepared by the aforementioned method for preparing a photochromic polyamide material.

[0051] Optical devices mainly include two categories: optical elements and fiber optic devices. Optical elements encompass planar optical elements, spherical optical elements, molded glass aspherical lenses, etc.; fiber optic devices include coated fiber optic devices, collimators, acousto-optic devices, etc. Their application areas cover WSS in optical communication, coherent optical modules, 5G fronthaul optical modules, data center optical modules, as well as beam combiners and splitters for lithography machine optical systems.

[0052] The application of a polymer in the preparation of smart coatings, wherein the polymer is the above-mentioned photochromic polyamide material, or is prepared by the above-mentioned method for preparing a photochromic polyamide material.

[0053] Example 0 - Synthesis of the precursor for photochromic polyamide materials: S1: In a dry three-necked flask, weigh 384.5 g of compound A-1 (2 mol) and add an appropriate amount of anhydrous toluene as solvent. Stir under nitrogen protection, and slowly add 96 g of compound A-2 (2 mol). Heat the reaction system to reflux temperature and maintain for 6 hours to ensure complete reaction. After the reaction is complete, cool to room temperature and remove the solvent from the reaction mixture using a rotary evaporator. Pour the residue into ice water and stir to precipitate a solid. Collect the product by filtration and wash repeatedly with deionized water until the filtrate is neutral. Recrystallize the crude product from anhydrous ethyl acetate to give 388.56 g of intermediate A-3, with a yield of 89%.

[0054] 1 H NMR (500 MHz, CDCl3) δ 7.13 (d, J = 14.8 Hz, 2H), 7.02 (d, J = 15.0Hz, 2H), 2.64 (s, 1H), 1.86 (s, 1H).

[0055] S2: In a dry three-necked flask, weigh 381.01 g of compound A-3 (1.75 mol) and add an appropriate amount of anhydrous toluene as a solvent. Under nitrogen protection, stir and slowly add 252.30 g of compound A-4 (1.75 mol). Heat the reaction system to reflux temperature and maintain for 5 hours to ensure complete reaction. After the reaction is complete, cool to room temperature, remove the solvent by rotary evaporation, and pour the residue into ice water while stirring to precipitate a solid. Collect the product by filtration and wash with deionized water until the filtrate is neutral. Recrystallize the crude product with anhydrous ethanol to finally obtain 482.68 g of compound A-5, with a yield of 80%.

[0056] 1 H NMR (500 MHz, CDCl3) δ 8.35 – 8.21 (m, 1H), 8.11 – 7.94 (m, 1H), 7.68 – 7.41 (m, 3H), 7.32 (dd, J = 14.9, 3.0 Hz, 1H), 7.13 (d, J = 14.8 Hz, 2H), 7.02 (d, J = 15.0 Hz, 2H), 6.76 (d, J = 21.8 Hz, 1H), 6.59 (d, J = 21.8 Hz, 1H).

[0057] S3: Dissolve A-5 (344.45 g / mol, 1.75 mol, 602.79 g) in 1000 mL of concentrated sulfuric acid, and slowly add concentrated nitric acid (2.0 equivalents) dropwise, maintaining the reaction temperature between 0 and 5 °C. After the addition is complete, continue stirring in an ice bath for 2 hours to ensure complete nitration. After the reaction is complete, slowly pour the reaction mixture into a large amount of ice water. Collect the precipitated solid by filtration and wash with cold water until neutral. Recrystallize the crude product from anhydrous ethanol to give 645.95 g of compound A-6, with a yield of 85%.

[0058] 1H NMR (500 MHz, CDCl3) δ 9.01 (s, 2H), 8.35 – 8.24 (m, 1H), 8.08 –7.92 (m, 1H), 7.67 – 7.39 (m, 3H), 7.32 (dd, J = 14.9, 3.0 Hz, 1H), 6.80 (d, J = 21.8 Hz, 1H), 6.62 (d, J = 21.8 Hz, 1H).

[0059] S4: 651 g of compound A-6 (434 g / mol, 1.5 mol) was added to a reactor and dissolved in 1000 mL of ethanol. Iron powder (5 equivalents) and concentrated hydrochloric acid (3 equivalents) were added, and the mixture was heated and stirred at 60 °C for 5 hours. After the reaction was complete, the mixture was filtered while hot to remove insoluble iron residue. The filtrate was concentrated to dryness using a rotary evaporator. The concentrate was dissolved in water and adjusted to alkalinity with ammonia. The precipitated product was collected by vacuum filtration to obtain 472.04 g of compound A-7, with a yield of 84%.

[0060] 1 H NMR (500 MHz, CDCl3) δ 8.29 (dd, J = 7.3, 1.6 Hz, 1H), 8.02 (dt, J =7.3, 1.5 Hz, 1H), 7.61 (d, J = 7.5 Hz, 1H), 7.51 (dtd, J = 21.4, 7.5, 1.6 Hz,2H), 7.32 (dd, J = 7.5, 1.4 Hz, 1H), 6.76 (d, J = 10.8 Hz, 1H), 6.61 (d, J =10.8 Hz, 1H), 5.88 (s, 2H).

[0061] S5: Compound A-7 (374.48 g / mol, 1 mol, 374.48 g) was dissolved in 300 mL of hydrochloric acid. Sodium nitrite solution (1.1 equivalents) was added at 0–5 °C to form a diazonium salt. After the reaction was complete, ice water was added and stirring continued to generate compound A-8 containing a hydroxyl group. The resulting solid was collected by filtration, washed with water until neutral, and finally yielded 300.96 g of A-8, with a yield of 80%.

[0062] 1H NMR (500 MHz, Chloroform ) δ 8.39 – 8.22 (m, 1H), 8.10 – 7.91 (m,1H), 7.68 – 7.21 (m, 4H), 6.93 – 6.69 (m, 3H), 6.56 (d, J = 21.8 Hz, 1H), 3.80(s, 2H).

[0063] S6: In a dry three-necked flask, weigh A-8 (0.75 mol, 282.33 g) and dissolve it in 300 mL of anhydrous dichloromethane with stirring. Slowly add the bromoalkylamine derivative 1-1 (0.75 mol, 273.04 g) and triethylamine (1.5 equivalents, 112.5 g), and stir the reaction at room temperature for 6 hours. After the reaction is complete, wash the organic phase with water, separate the organic layer, remove the solvent by rotary evaporation, and obtain the crude product. Purify by column chromatography to obtain 1-2, with a yield of 440.64 g, which is 85%.

[0064] 1 H NMR (500 MHz, CDCl3) δ 8.38 – 8.10 (m, 1H), 8.10 – 7.75 (m, 1H), 7.72 – 7.11 (m, 4H), 6.93 – 6.28 (m, 4H), 4.39 (s, 2H), 4.21 – 3.93 (m, 4H), 3.31 – 2.98 (m, 4H), 2.15 – 1.86 (m, 4H), 1.42 (s, 18H).

[0065] S7: Dissolve 1-2 (0.5 mol, 345.12 g) in 200 mL of dichloromethane, add trifluoroacetic acid (2.0 equivalent, 103.0 g), and stir at room temperature for 4 hours to remove the Boc protecting group. After the reaction is complete, remove the solvent using a rotary evaporator, and wash the residue with saturated sodium bicarbonate solution until neutral to give 1-3, with a yield of 333.30 g and a yield of 85%.

[0066] 1 H NMR (500 MHz, CDCl3) δ 8.34 – 8.15 (m, 1H), 8.08 – 7.83 (m, 1H), 7.78 – 7.10 (m, 4H), 6.98 – 6.21 (m, 4H), 4.11 (t, J= 9.8 Hz, 4H), 3.13 –2.54 (m, 4H), 2.27 – 1.79 (m, 4H), 1.40 (s, 4H).

[0067] The reaction formulas for steps S1-S7 are as follows: .

[0068] Example 1 - Synthesis of photochromic polyamide material T-1: Example 1 uses the precursor of the photochromic material from Example 0.

[0069] S8: In a dry three-necked flask, weigh diamine compound 1-3 (0.25 mol, 122.88 g) and dicarboxylic acid derivative 1-4 (0.25 mol, 33.01 g), and add dehydrating agent DCC (1.5 equivalents, 77.37 g). Dissolve all substances in 150 mL of anhydrous dichloromethane. Under nitrogen protection, stir for 24 hours to carry out dehydration condensation polymerization. After the reaction is complete, wash the organic layer with water and separate and purify. Remove the solvent by rotary evaporation to obtain the crude product. Purify the crude product by precipitation in methanol to collect the target amide polymer T-1, with a yield of 174.4 g, which is 80%.

[0070] 1 H NMR (500 MHz, CDCl3) δ 8.12 (dddd, J = 13.1, 6.8, 4.8, 3.5 Hz, 2H),7.75 – 7.09 (m, 4H), 6.89 – 6.30 (m, 4H), 5.93 (s, 1H), 4.11 (t, J = 14.9 Hz, 4H), 2.83 (ddt, J = 52.2, 16.4, 9.2 Hz, 8H), 2.10 – 1.64 (m, 4H), 1.19 (s, 1H).

[0071] The reaction formula for Example 1 is: .

[0072] Example 2 - Synthesis of photochromic polyamide material T-2: The basic steps of Example 2 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, weigh diamine compound 1-3 (0.25 mol, 122.54 g) and dicarboxylic acid derivative 2-4 (0.25 mol, 33.01 g), add dehydrating agent DCC (1.5 equivalents, 77.37 g), and dissolve all substances in 150 mL of anhydrous dichloromethane. The reaction is carried out under nitrogen protection with stirring for 24 hours to perform dehydration polycondensation. After the reaction is complete, wash the organic layer with water and remove the solvent by rotary evaporation. The crude product is purified by precipitation in methanol, yielding the target amide polymer T-2 in a yield of 114.21 g, representing a yield of 74%.

[0073] 1 H NMR (500 MHz, CDCl3) δ 8.42 – 8.14 (m, 1H), 8.07 – 7.82 (m, 1H), 7.78 – 7.08 (m, 4H), 6.92 – 6.27 (m, 4H), 5.21 (s, 1H), 4.10 (t, J = 14.9 Hz, 4H), 3.12 (t, J = 15.4 Hz, 2H), 2.66 (t, J = 15.2 Hz, 2H), 2.46 – 2.19 (m, 4H), 2.19 – 1.56 (m, 6H), 1.17 (s, 1H).

[0074] The reaction formula for Example 2: .

[0075] Example 3 - Synthesis of photochromic polyamide material T-3: The basic steps of Example 3 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.25 mol (122.54 g) of diamine compound 1-3 and 0.25 mol (39.78 g) of dicarboxylic acid derivative 3-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out the dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, and the solvent was removed by rotary evaporation. The crude product was collected by precipitation in methanol, yielding 130.80 g, representing a yield of 81%.

[0076] 1 H NMR (500 MHz, CDCl3) δ 8.12 (dddd, J= 7.8, 6.8, 4.8, 3.5 Hz, 2H),7.75 – 7.06 (m, 4H), 7.06 – 6.19 (m, 4H), 5.26 (s, 1H), 4.11 (t, J = 14.5 Hz, 4H), 3.13 (t, J = 15.4 Hz, 2H), 2.88 – 2.26 (m, 4H), 2.04 (dq, J = 29.8, 14.4Hz, 6H), 1.72 – 0.90 (m, 9H).

[0077] The reaction formula for Example 3: .

[0078] Example 4 - Synthesis of photochromic polyamide material T-4: The basic steps of Example 4 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.25 mol (122.54 g) of diamine compound 1-3 and 0.25 mol (41.51 g) of dicarboxylic acid derivative 4-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out the dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, and the solvent was removed by rotary evaporation. The crude product was collected by precipitation in methanol, yielding the target product T-4, with a yield of 137.58 g, representing a yield of 84%.

[0079] 1 H NMR (500 MHz, CDCl3) δ 8.11 (dd, J = 127.5, 42.5 Hz, 6H), 7.77 – 7.10(m, 4H), 6.92 – 6.37 (m, 4H), 6.15 (s, 1H), 4.11 (s, 4H), 3.42 (s, 2H), 2.67(s, 2H), 2.00 (d, J = 20.0 Hz, 4H), 1.17 (s, 1H).

[0080] The reaction formula for Example 4: .

[0081] Example 5 - Synthesis of photochromic polyamide material T-5: The basic steps of Example 5 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.25 mol (122.54 g) of diamine compound 1-3 and 0.25 mol (48.52 g) of dicarboxylic acid derivative 5-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out the dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, and the solvent was removed by rotary evaporation. The crude product was collected by precipitation in methanol, yielding the target product T-5, with a yield of 138.54 g, representing a yield of 81%.

[0082] 1 H NMR (500 MHz, CDCl3) δ 8.40 – 7.65 (m, 4H), 7.65 – 7.15 (m, 4H), 7.13 – 6.09 (m, 5H), 4.37 – 3.85 (m, 4H), 3.42 (t, J = 11.4 Hz, 2H), 2.67 (t, J = 9.6 Hz, 2H), 2.22 (s, 6H), 2.11 – 1.75 (m, 4H), 1.27 (s, 1H).

[0083] The reaction formula for Example 5: .

[0084] Example 6 - Synthesis of photochromic polyamide material T-6: The basic steps of Example 6 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.25 mol (122.54 g) of diamine compound 1-3 and 0.25 mol (69.54 g) of dicarboxylic acid derivative 6-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out the dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, and the solvent was removed by rotary evaporation. The crude product was collected by precipitation in methanol, yielding 158.93 g, representing a yield of 83%.

[0085] 1H NMR (500 MHz, CDCl3) δ 8.43 – 6.34 (m, 12H), 5.90 (s, 1H), 4.11 (s, 4H), 3.42 (s, 2H), 2.67 (s, 2H), 2.00 (d, J = 20.0 Hz, 4H), 1.35 (s, 18H), 1.17 (s, 1H).

[0086] The reaction formula for Example 6: .

[0087] Example 7 - Synthesis of photochromic polyamide material T-7: The basic steps of Example 7 are the same as steps S1-S7 of Example 1, except for step S8; S8: In a dry three-necked flask, 0.25 mol (122.54 g) of diamine compound 1-3 and 0.25 mol (48.52 g) of dicarboxylic acid derivative 7-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out a dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, and the solvent was removed by rotary evaporation. The crude product was collected by precipitation in methanol, yielding the target product T-7, with a yield of 131.52 g, representing a yield of 78%.

[0088] 1 H NMR (500 MHz, CDCl3) δ 8.45 – 7.08 (m, 10H), 6.72 (dd, J = 71.5, 53.3Hz, 4H), 5.47 (s, 1H), 4.36 – 3.53 (m, 8H), 3.13 (s, 2H), 2.67 (s, 2H), 1.98 (s, 4H), 1.33 (s, 1H).

[0089] The reaction formula for Example 7: .

[0090] Example 8 - Synthesis of photochromic polyamide material T-8: The basic steps of Example 8 are the same as steps S1-S5 of Example 1, except for steps S6 and onwards; S6: In a dry three-necked flask, weigh A-8 (0.75 mol, 282.33 g) and dissolve it in 300 mL of anhydrous dichloromethane with stirring. Slowly add 8-1 (0.75 mol, 167.27 g) and triethylamine (1.5 equivalents, 112.5 g), and stir the reaction at room temperature for 6 hours. After the reaction is complete, wash the organic phase with water, separate the organic layer, and remove the solvent by rotary evaporation to obtain the crude product. Purify the crude product by column chromatography to obtain 8-2, with a yield of 374.46 g, which is 84%.

[0091] 1 H NMR (500 MHz, CDCl3) δ 8.41 – 8.19 (m, 1H), 8.11 – 7.90 (m, 1H), 7.73 – 7.15 (m, 4H), 6.93 – 6.41 (m, 4H), 4.50 (s, 2H), 4.36 – 4.07 (m, 4H), 3.56 – 3.10 (m, 4H), 1.42 (s, 18H).

[0092] S7: Dissolve 8-2 (0.5 mol, 331.10 g) in 200 mL of anhydrous dichloromethane, add trifluoroacetic acid (2.0 equivalent, 103.0 g), and stir at room temperature for 4 hours to remove the Boc protecting group. After the reaction is complete, remove the solvent using a rotary evaporator, and neutralize the residue with saturated sodium bicarbonate solution to give crude product 8-3, with a yield of 187.36 g and a yield of 81%.

[0093] 1 H NMR (500 MHz, CDCl3) δ 8.45 – 8.18 (m, 1H), 8.14 – 7.83 (m, 1H), 7.73 – 7.16 (m, 4H), 7.04 – 6.38 (m, 4H), 4.47 – 3.99 (m, 4H), 3.53 – 3.09 (m, 4H), 1.26 (s, 4H).

[0094] S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (29.51 g) of dicarboxylic acid derivative 8-4 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added and dissolved in 150 mL of anhydrous dichloromethane. The mixture was stirred for 24 hours under nitrogen protection to carry out a dehydration condensation reaction. After the reaction was complete, the organic phase was washed with water, the organic layer was separated, the solvent was removed by rotary evaporation, and the target amide polymer T-8 was obtained by precipitation in methanol, with a yield of 116.64 g and a yield of 82%.

[0095] 1 H NMR (500 MHz, CDCl3) δ 8.41 – 8.19 (m, 1H), 8.11 – 7.85 (m, 1H), 7.70 – 7.36 (m, 3H), 7.31 (dd, J = 15.0, 3.1 Hz, 1H), 6.75 (t, J = 10.9 Hz, 2H), 6.58 (d, J = 21.8 Hz, 1H), 6.46 (s, 1H), 5.50 (s, 1H), 4.40 – 4.08 (m,4H), 3.48 (t, J = 13.6 Hz, 2H), 3.10 (t, J = 8.4 Hz, 2H), 2.88 (td, J = 12.5,0.6 Hz, 2H), 2.68 – 2.44 (m, 2H), 1.14 (s, 1H).

[0096] The reaction formula for Example 8: .

[0097] Example 9 - Synthesis of photochromic polyamide material T-9: The basic steps of Example 9 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (33.01 g) of dicarboxylic acid derivative 9-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 150 mL of anhydrous dichloromethane. The reaction was stirred for 24 hours under nitrogen protection to promote the dehydration and polycondensation reaction. After the reaction was complete, the organic layer was washed with water, and the solvent was removed by rotary evaporation to obtain the crude product. Finally, the target amide polymer T-9 was obtained by precipitation in methanol, with a yield of 115.34 g and a yield of 86%.

[0098] 1 H NMR (500 MHz, CDCl3) δ 8.48 – 7.81 (m, 2H), 7.76 – 7.07 (m, 4H), 6.86 – 6.53 (m, 3H), 6.45 (s, 1H), 5.84 (s, 1H), 4.50 – 4.06 (m, 4H), 3.48(t, J = 10.0 Hz, 2H), 3.11 (t, J = 9.1 Hz, 2H), 2.55 – 1.76 (m, 6H), 1.29 (s, 1H).

[0099] The reaction formula for Example 9: .

[0100] Example 10 - Synthesis of photochromic polyamide material T-10: The basic steps of Example 10 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (43.52 g) of dicarboxylic acid derivative 10-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 200 mL of anhydrous dichloromethane. The reaction was stirred for 24 hours under nitrogen protection to promote dehydration and polycondensation. After the reaction was complete, the organic layer was washed with water, and the solvent was removed by rotary evaporation. The crude product was precipitated in methanol, filtered, and collected to obtain the target amide polymer T-10, with a yield of 126.8 g, representing a yield of 83%.

[0101] 1H NMR (500 MHz, CDCl3) δ 8.43 – 7.75 (m, 2H), 7.65 – 7.00 (m, 4H), 6.86 – 6.34 (m, 4H), 6.16 (s, 1H), 4.27 (t, J = 18.0 Hz, 4H), 3.74 – 2.77 (m,4H), 2.50 – 1.97 (m, 4H), 1.77 – 0.85 (m, 9H).

[0102] The reaction formula for Example 10: .

[0103] Example 11 - Synthesis of photochromic polyamide material T-11: The basic steps of Example 11 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (41.53 g) of dicarboxylic acid derivative 11-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 200 mL of anhydrous dichloromethane. The reaction was stirred for 24 hours under nitrogen protection to promote the dehydration and polycondensation reaction. After the reaction was complete, the organic layer was washed with water, and the solvent was removed by rotary evaporation. The crude product was precipitated in methanol and filtered to obtain the target amide polymer T-11, with a yield of 130.5 g and a yield of 84%.

[0104] 1 H NMR (500 MHz, CDCl3) δ 8.45 – 7.81 (m, 6H), 7.73 – 7.13 (m, 4H), 7.07 – 6.08 (m, 5H), 4.50 – 3.92 (m, 4H), 3.53 (td, J = 18.7, 0.6 Hz, 2H), 3.11 (t, J = 17.8 Hz, 2H), 1.12 (s, 1H).

[0105] The reaction formula for Example 11: .

[0106] Example 12 - Synthesis of photochromic polyamide material T-12: The basic steps of Example 12 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (48.52 g) of dicarboxylic acid derivative 12-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 150 mL of anhydrous dichloromethane. The reaction was carried out under nitrogen protection with stirring for 24 hours for dehydration and polycondensation. After the reaction was complete, the organic layer was washed with water, and the solvent was removed by rotary evaporation. The crude product was purified by precipitation in methanol, collected, and dried to obtain the target amide polymer T-12, with a yield of 132.23 g and a yield of 84%.

[0107] 1 H NMR (500 MHz, CDCl3) δ 8.45 – 7.11 (m, 8H), 6.84 – 5.95 (m, 5H), 4.30 (dt, J = 35.8, 9.3 Hz, 4H), 3.52 (td, J = 18.7, 0.6 Hz, 2H), 3.10 (t, J =17.8 Hz, 2H), 2.22 (s, 6H), 1.14 (s, 1H).

[0108] The reaction formula for Example 12: .

[0109] Example 13 - Synthesis of photochromic polyamide material T-13: The basic steps of Example 13 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (69.54 g) of dicarboxylic acid derivative 13-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 150 mL of anhydrous dichloromethane. Under nitrogen protection, the mixture was stirred for 24 hours to carry out dehydration and polycondensation. After the reaction was completed, the organic layer was washed with water, and the solvent was removed by rotary evaporation. The crude product was precipitated in methanol, collected, and dried to obtain the target amide polymer T-13, with a yield of 153.92 g and a yield of 84%.

[0110] 1 H NMR (500 MHz, CDCl3) δ 8.42 – 7.77 (m, 4H), 7.72 – 7.08 (m, 5H), 6.83 (t, J= 10.9 Hz, 2H), 6.41 (s, 1H), 5.95 (d, J = 21.8 Hz, 1H), 4.49 – 3.98(m, 4H), 3.67 – 3.34 (m, 2H), 3.11 (t, J = 17.9 Hz, 2H), 1.59 (s, 1H), 1.35 (s, 17H).

[0111] The reaction formula for Example 13: .

[0112] Example 14 - Synthesis of photochromic polyamide material T-14: The basic steps of Example 14 are the same as steps S1-S7 of Example 8, except for step S8; S8: In a dry three-necked flask, 0.25 mol (115.53 g) of diamine compound 8-3 and 0.25 mol (48.52 g) of dicarboxylic acid derivative 14-1 were weighed, and 1.5 equivalents (77.37 g) of dehydrating agent DCC were added. All substances were dissolved in 150 mL of anhydrous dichloromethane. Under nitrogen protection, the reaction was stirred for 24 hours to carry out dehydration polycondensation. After the reaction was completed, the organic layer was washed with water, and the solvent was removed by rotary evaporation. The crude product was precipitated in methanol, collected, and dried to finally obtain the target amide polymer T-14, with a yield of 137.85 g and a yield of 84%.

[0113] 1 H NMR (500 MHz, CDCl3) δ 8.48 – 7.11 (m, 10H), 6.92 – 6.37 (m, 4H), 5.92 (s, 1H), 4.51 – 2.70 (m, 12H), 1.35 (s, 1H).

[0114] The reaction formula for Example 14: .

[0115] The performance tests were performed on T1-T14 corresponding to Examples 1-14, and the results are shown in Table 1: ① Photochromic performance test: Each material was dissolved and prepared into a thin film, which was then coated onto a glass substrate, ensuring a uniform coating. The thin films were irradiated with a 365 nm ultraviolet light source, and the time it took for the materials to change from colorless to colored was recorded. After irradiation was stopped, the time it took for the materials to return to a colorless state was recorded. Each material underwent multiple light cycles to observe its photochromic response speed and repeatability.

[0116] ② Thermal stability test: Thermogravimetric analysis (TGA) was used to measure the weight loss of the samples as the temperature increased. The samples were heated in a nitrogen atmosphere, and the decomposition temperature of the material was recorded. The glass transition temperature (Tg) of the samples was measured using differential scanning calorimetry (DSC). The temperature range was set from 25 °C to 400 °C, with a heating rate of 10 °C / min, to evaluate the thermal stability of the material.

[0117] ③ Mechanical performance testing: Each material was prepared into a film of uniform thickness, and its tensile strength and elongation at break were measured using a tensile tester. The tensile speed was set to 5 mm / min, and the film was stretched until it broke to evaluate its mechanical properties.

[0118] ④ Weather resistance test: The thin film samples were subjected to accelerated aging tests in an environment with ultraviolet light, 85% humidity, and 60°C for 1000 hours. The photochromic properties of the materials were periodically tested, and the rate of change of photochromic properties during the aging process was recorded to evaluate the materials' resistance to ultraviolet aging and long-term stability under harsh environments.

[0119] illustrate: The photochromic properties of Examples 1-14 demonstrate their promising potential in dynamic optics applications, exhibiting short response times and stability over multiple cycles. Thermal stability tests show the material's stability in high-temperature environments; decomposition temperature and Tg results indicate its suitability for high-temperature applications. Mechanical property tests highlight the material's tensile strength and flexibility, making it particularly suitable for applications requiring durability. Weather resistance tests show that the material maintains good photosensitivity under ultraviolet light, high temperature, and high humidity conditions, making it suitable for applications requiring long-term outdoor exposure.

[0120] 1. Regarding the high-efficiency photochromic performance, the photochromic response time is 9-16s, and the recovery time is 22-30s, indicating that the photochromic material of this invention can rapidly change color under ultraviolet light irradiation and recover its original state under visible light or heating conditions. This material has a faster light response speed, higher stability, and the photochromic process is unaffected by environmental factors, exhibiting excellent recyclability. This design solves the problems of weakened light response and reduced color change depth in traditional naphthol-pyran materials, making it particularly suitable for applications such as smart coatings and optical devices.

[0121] 2. The decomposition temperature is 285-315℃, and the Tg is 89-95℃. The decomposition temperature and Tg results indicate that it is suitable for high-temperature applications.

[0122] 3. Regarding the improvement of mechanical properties and durability, the tensile strength is 53-61 MPa and the elongation at break is 15-20%. After introducing the polyamide matrix, the material shows a significant improvement in mechanical properties, especially in tensile strength.

[0123] 4. Regarding weather resistance, compared to ordinary scenarios, after 1000 hours of accelerated aging treatment, the change rate of weather resistance photochromic properties is only 3-5%. This characteristic enables the material to maintain functional integrity during long-term use, demonstrating the material's resistance to ultraviolet aging and its long-term stability in harsh environments. It is particularly suitable for applications with high mechanical strength requirements, such as intelligent building coatings and vehicle exterior coatings.

[0124] In summary, this invention combines photochromic functionality with polyamide materials. This structure not only ensures photochromic performance but also significantly improves the material's mechanical strength, durability, and chemical stability. The material retains its photochromic function through multiple light exposure cycles with a short response time and rapid recovery. Furthermore, the material exhibits strong weather resistance, maintaining stable photochromic performance under high temperature, high humidity, and ultraviolet light exposure conditions. This material maintains its performance unchanged in outdoor environments or harsh industrial conditions, demonstrating good aging resistance and environmental adaptability. This expands the application scenarios of photochromic materials and provides a novel solution for the future development of optoelectronic smart materials.

[0125] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A precursor for a photochromic material, characterized in that, Its molecular formula is: ； Where G is the active functional group; m is a natural number, m≥0; and n is the degree of polymerization.

2. The precursor of a photochromic material according to claim 1, characterized in that, G can be a hydroxyl, carboxyl, aldehyde, carbonyl, amino, nitro, halogen, alkynyl, epoxy, or isocyanate group.

3. A method for preparing a precursor of a photochromic material, characterized in that, Includes the following steps: S1: Dissolve compounds A-1 and A-2 in a solvent, stir, heat to 100-120℃, and react under a protective atmosphere; cool to room temperature, remove the solvent, and separate and purify to obtain intermediate A-3; Compound A-1 is Compound A-2 is sodium acetylene; intermediate A-3 is... ; S2: Dissolve intermediate A-3 in a flux, add naphthol as compound A-4, add sodium hydroxide, and react with stirring until the nucleophilic substitution reaction is complete; after the reaction, separate the organic phase, dry, filter, and remove the solvent to obtain compound A-5; compound A-5 is... ; S3: Dissolve compound A-5 in concentrated sulfuric acid, add concentrated nitric acid dropwise, control the reaction temperature at 0-5℃, and stir the reaction in an ice bath; after the reaction is complete, slowly pour the reaction mixture into ice water, filter and collect the precipitate, wash the precipitate to obtain intermediate A-6; intermediate A-6 is ; S4: Dissolve intermediate A-6 in a solvent, add a reducing agent and concentrated hydrochloric acid, and react at 30-90℃ with stirring, maintaining an acidic environment during the reaction; after the reaction is complete, remove the reducing agent, concentrate the filtrate to dryness, dissolve the concentrate in water and adjust to alkalinity, collect the precipitated product by vacuum filtration to obtain intermediate A-7; intermediate A-7 is ; S5: Dissolve intermediate A-7 in acid, and slowly add sodium nitrite solution at 0-5℃ to generate diazonium salt; after the reaction is complete, add ice water and stir. Add excess water, filter and collect the product, and wash with water until neutral to obtain intermediate A-8; intermediate A-8 is... ; S6: Add solvent to intermediate A-8 and dissolve it under stirring. Add bromoalkane derivative A-9 and triethylamine and stir to react. After the reaction is complete, wash the organic phase with water, separate the organic layer, dry and purify to obtain the precursor A-111 of the photochromic material. Bromoalkyl derivative A-9 is The proto-body A-111 is: G is the active functional group, and m is a natural number.

4. The method for preparing a precursor of a photochromic material according to claim 3, characterized in that, In step S6, intermediate A-8 is dissolved in solvent by stirring, and bromoalkane derivative A-9 with Boc anhydride protecting the active functional group G and triethylamine are added and stirred to react. After the reaction is completed, the organic phase is washed with water, the organic layer is separated, dried and purified to obtain compound A-10. A-9, a bromoalkylamine derivative, is Intermediate A-10 is ; After step S6, continue to step S7; S7: Dissolve intermediate A-10 in a solvent, add trifluoroacetic acid, remove the Boc protecting group, and generate the precursor A-111 of the photochromic material.

5. A photochromic polyamide material, characterized in that, Its molecular structural formula is: ； Wherein, R is a hydrocarbon group or a derivative of a hydrocarbon group; m is a natural number, m≥0; n is the degree of aggregation.

6. The photochromic polyamide material according to claim 5, characterized in that, The molecular structure formula is one of the following substructure formulas: 。 7. A method for preparing a photochromic polyamide material, characterized in that, Includes the following steps: Will The dicarboxylic acid monomer is added to a solvent, a dehydrating agent and a catalyst are added, and the reaction is carried out under a protective atmosphere to promote the polymerization of amino and carboxyl groups. After the reaction, the mixture is purified to obtain... ; The molecular structure of a dicarboxylic acid monomer is HOOC-R-COOH; R is a hydrocarbon group or a derivative of a hydrocarbon group.

8. A photoinitiator, characterized in that, include: Photochromic polyamide materials; The photochromic polyamide material is a photochromic polyamide material according to any one of claims 5-6, or is prepared by the preparation method of a photochromic polyamide material according to claim 7.

9. An application of a polymer in optical devices, characterized in that, The polymer is a photochromic polyamide material as described in any one of claims 5-6, or is prepared by the preparation method of a photochromic polyamide material as described in claim 7.

10. The application of a polymer in the preparation of smart coatings, characterized in that, The polymer is a photochromic polyamide material as described in any one of claims 5-6, or is prepared by the preparation method of a photochromic polyamide material as described in claim 7.

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