CN115386081B - A method for constructing second-order nonlinear optical polymer materials by in-situ thermal crosslinking reaction - Google Patents

Abstract

The invention relates to the technical field of material science, in particular to a method for constructing a second-order nonlinear optical polymer material through an in-situ thermal crosslinking reaction. The group is thermally cross-linked monomer, and the second-order nonlinear optical polymer network structure is prepared: The present invention utilizes maleimide-functionalized chromophores and azide-functionalized chromophores to prepare second-order nonlinear optical polymer materials through in-situ thermal crosslinking. The monomer synthesis operation is simple, the reaction time is short, and the conditions Gentle and simple in-situ thermal cross-linking in the polarization heating process forms a second-order nonlinear optical polymer network structure, and its d ₃₃ value is as high as 222pm/V measured by the in-situ second harmonic generation method, T _80% reaches 99.7°C, and the second-order nonlinear optical coefficient of the non-resonant enhanced part related to light transmission reaches 49pm/V, which is the highest value of azobenzene-based second-order nonlinear optical polymers.

Description

A method for constructing second-order nonlinear optical polymer materials by in-situ thermal crosslinking reaction

technical field

The invention relates to the technical field of material science, in particular to a method for constructing a second-order nonlinear optical polymer material through an in-situ thermal crosslinking reaction.

Background technique

If organic second-order nonlinear optical materials are to replace commercialized inorganic crystal materials and meet the requirements of practical applications, the following conditions must be met at the same time: a sufficiently large macroscopic second-order nonlinear optical effect value (d ₃₃ ), good stability (T _80% ) and the lowest possible optical loss. In fact, if only for a specific index, the research results at the beginning of this century can meet most of the requirements. progress. However, it is very difficult to meet these three requirements at the same time. The reason is that the three practical requirements are not isolated, but closely related and mutually restrictive: (1) Increasing the hyperpolarizability of chromophore molecules can improve the macroscopic second-order nonlinear optical effect of the polarized film, However, it will also lead to a red shift of the absorption wavelength of the chromophore, thereby increasing the light propagation loss; (2) increasing the dipole moment of the chromophore will increase the electrostatic interaction between the chromophore molecules, resulting in a decrease in the orientation order The degree of polarization may eventually reduce the macroscopic second-order nonlinear optical effect of the polarized film; (3) increasing the content of the chromophore can theoretically improve the macroscopic second-order nonlinear optical effect of the polarized film, but at the same time the chromophore The electrostatic interaction between molecules will also be enhanced, which will inhibit the increase of the macroscopic second-order nonlinear optical coefficient; (4) increasing the glass transition temperature of the polymer is very important for improving the orientation stability of the polarized film, but Such materials with a high glass transition temperature have much harsher requirements on polarization conditions and are often difficult to polarize. These mutually restrictive relationships are summarized by scientists as the contradiction between "nonlinearity" and "stability" and the contradiction between "nonlinearity" and "transparency".

Among many chromophores, azobenzene chromophores are often used as the building blocks of second-order nonlinear optical materials due to their simple synthesis steps and excellent photothermal stability. The same contradiction also exists in optical materials: the d ₃₃ value of the azobenzene chromophore polymer with better stability is often not high; while the azobenzene chromophore dendrimer with a higher d ₃₃ value is stable However, regardless of dendrimers or polymers, the second-order nonlinear optical coefficient d _33(∞) , which can reflect the non-resonance enhanced part of the optical transparency of the material, has not increased significantly.

In summary, it is necessary to design and synthesize azobenzene second-order nonlinear optical materials with a balance of "nonlinearity-stability-transparency".

Contents of the invention

The purpose of the present invention is to provide a method for constructing second-order nonlinear optical polymer materials by in-situ thermal cross-linking reaction. The monomer synthesis operation is simple, the reaction time is short, the conditions are mild, and the in-situ thermal cross-linking reaction can be performed without solvent The second-order nonlinear optical polymer network structure can be constructed.

The solution adopted by the present invention to achieve the purpose is: a method for constructing second-order nonlinear optical polymer materials by in-situ thermal crosslinking reaction, using maleimide-functionalized chromophores and azide-functionalized chromophores The group is thermally cross-linked monomer, and the second-order nonlinear optical polymer network structure is prepared:

Among them, MA is the maleimide functional group; R ₁ and R ₂ are both second-order nonlinear optical molecules; m is the functionalization number of maleimide functional group on R ₁ molecule; n is the -N ₃ functional group in The number of functionalizations on the _R2 molecule.

Preferably, the R ₁ and R ₂ are respectively selected from any one of the chromophores of the D-π-A donor acceptor push-pull electron structure, and may be the same or different.

Preferably, the R ₁ and R ₂ are respectively selected from any one of azo chromophore, FTC chromophore, CLD chromophore and DANS chromophore, and may be the same or different.

Further, when R ₁ and R ₂ are respectively selected from azo-based chromophores, the azo-based chromophores are nitroazobenzene or sulfone-azobenzene chromophores.

Further applying sulfone-based azobenzene as a spacer chromophore to this scheme can improve the optical transparency on the basis of further increasing the d ₃₃ value and T _80% .

Preferably, the R ₁ and R ₂ are single chromophore molecules or multi-chromophore molecules.

Preferably, m≥2, n≥2.

Preferably, the R ₁ -mMA is prepared by esterifying hydroxyl-containing chromophore molecules with maleimide alkyl carboxylic acid.

Further, the maleimide alkyl carboxylic acid is selected from at least one of maleimide propionic acid, maleimide butyric acid, and maleimide caproic acid.

Preferably, the R ₂ -nN ₃ is prepared by substituting a halogenated chromophore molecule or a p-toluenesulfonate chromophore molecule with an azide reagent.

Further, the azide reagent is selected from sodium azide, trimethylsilane azide, diphenylphosphoryl azide, tributyltin azide and tetrabutylammonium azide.

Preferably, the R ₁ -mMA and R ₂ -nN ₃ are dissolved in a solvent to prepare a solution, and then coated on the surface of a conductive substrate, and polarized at a certain temperature after drying to form a film to obtain the Second-order nonlinear optical polymer materials.

The two-component monomers R ₁ -mMA and R ₂ -nN ₃ are doped with spin coating to form a second-order nonlinear optical polymer film through in-situ polarization thermal crosslinking, compared with the complicated synthesis of conventional polymers And the difficult purification process, the operation is easier.

Preferably, the solvent is any one of tetrahydrofuran, dichloromethane, chloroform, and acetone, and R ₁ -mMA and R ₂ -nN ₃ are mixed according to the stoichiometric ratio and prepared so that the total concentration is 20-40mg/mL solution.

Preferably, the temperature of the polarization process is 25-150°C.

Generally, the polarization voltage used is 7000-8000V, the polarization distance is 5-10mm, and the heating rate is 5-10℃/min.

The present invention has the following advantages and beneficial effects:

The method of the present invention utilizes a maleimide-functionalized chromophore and an azide-functionalized chromophore to prepare a second-order nonlinear optical polymer material through in-situ thermal crosslinking, and the monomer synthesis operation is simple and the reaction time is short , under mild conditions, and form a second-order nonlinear optical polymer network structure in a simple in-situ thermal crosslinking manner during polarized heating.

The second-order nonlinear optical polymer network structure prepared by the method of the present invention has a d ₃₃ value as high as 222pm/V and a T _80% of 99.7°C as measured by the in-situ second harmonic generation method, and is related to the light transmittance The second-order nonlinear optical coefficient of the non-resonance enhanced part reaches 49pm/V, which is the highest value of the second-order nonlinear optical polymer of azobenzene. Compared with the preheated film, that is, the film obtained by crosslinking or polymerization before polarization shows higher d ₃₃ value, but the thermal stability of the two is almost the same. The necessity of the in situ polarized thermal crosslinking process is illustrated.

The method of the invention is simple and convenient to synthesize and operate, and constructs an azobenzene second-order nonlinear optical material with balanced "non-linearity-stability-light transmission", which is suitable for wide application.

Description of drawings

Fig. 1 is each doping monomer infrared spectrum (1a) and the infrared spectrum (1b) before and after heating of doped film in embodiment 1-4;

Fig. 2 is the solubility test of the products after polarization of Examples 1-4.

Detailed ways

For a better understanding of the present invention, the following examples are further descriptions of the present invention, but the content of the present invention is not limited to the following examples.

In the following examples, compound naming: follow-up to name the compound with an abbreviation, taking T3MA as an example, "T" here represents the three chromophores (the default is an azo chromophore if there is no other mark), and "MA" represents the Malay Imide functional group, "3" indicates the number of MA functionalization; similar to TS2N ₃ , "T" here indicates three chromophores, "S" indicates that the chromophore type is a sulfone azobenzene chromophore, " N ₃ ″ represents the azide functional group, and “2” represents the N ₃ functionalized number. For a single chromophore, take N2N ₃ as an example, "N" means that the chromophore type is nitroazobenzene chromophore, "2N ₃ " is consistent with the above, similar to F2MA as an example, "F" means bio The chromophore type is FTC chromophore, and "2MA" is consistent with the above.

Example 1:

Synthesis of T3MA:

The reaction formula is:

The specific steps are: put a magnet in the Schlenk bottle, weigh compound 1 (300.0mg, 0.61mmol), compound 2 (816.0mg, 1.81mmol), CuSO ₄ 5H ₂ O (60.5mg, 0.24mmol), After weighing VcNa (359.0mg, 1.81mmol), quickly stopper the saline stopper and pump for ventilation several times; take another eggplant-shaped bottle, add 40mL tetrahydrofuran and 6mL water into it, and put it under ultrasonic exhaust for 10-15min. 10 mL of the mixed solvent was injected into a Schlenk bottle under ventilation under ventilation, and reacted at 30° C. for 3-4 hours, and the reaction progress was monitored by TLC. After the reaction was completed, 100 mL of water was added to the reaction liquid to quench the reaction, and 50 mL of DCM was used to extract 3-4 times each time, the combined organic phase was washed 3-4 times with saturated brine, dried with anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain The crude product was subjected to column chromatography, and the raw material was recovered by rapid elution with the eluent DCM:EA=3:1, and then gradient elution with EtOH:EA=1:30 to obtain the red solid product T3OH (555 mg, 66%). ¹ H NMR (400MHz,CDCl ₃ ,298K),δ(TMS,ppm):7.84-7.67(m,12H,-ArH),7.62-7.52(m,3H,-ArH), 7.27(s,2H,- ArH), 6.66(d, J=8.8Hz, 4H, -ArH), 6.49(d, J=8.8Hz, 2H, -ArH), 4.35(t, J=6.0 Hz, 4H, -CH ₂ -), 4.18-4.04(m,6H,-CH ₂ -),3.71(t,J=6.0Hz,4H,-CH ₂ -),3.66-3.59(m,6H,-CH ₂ -),3.43(q,J =7.1Hz, 4H, -CH ₂ -), 3.33(t, J=7.8Hz, 4H, -CH ₂ -), 2.93(t, J=7.1Hz, 4H, -CH ₂ -), 2.19(p, J＝6.4Hz, 4H, -CH ₂ -), 1.87(p, J＝6.2Hz, 2H, -CH ₂ -), 1.67-1.52(m, 12H, -CH ₂ -), 1.47-1.32(m, 10H, -CH ₂ -), 1.19 (t, J=6.9Hz, 6H, -CH ₃ ). ¹³ C NMR (100MHz, CDCl ₃ , 298K), δ(ppm): 154.7, 151.2, 147.7, 147.1, 143.8 ,126.4,125.9,122.5,117.2,116.6,116.1,111.6,111.1,109.2,69.8,68.5,62.5,62.4,51.1,50.6,47.3,45.4,32.7,32.6,29.0,28.3,27.4,2 6.8, 26.0, 25.6 , 21.8, 12.4.

Put a magnet in the Schlenk bottle, weigh T3OH (100.0mg, 0.07mmol), compound 3 (50.0mg, 0.30mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide salt salt (EDC) (41.0mg, 0.22mmol), 4-dimethylaminopyridine p-toluenesulfonate (DPTS) (10.0mg, 0.03mmol), where EDC was weighed and added quickly due to its easy water absorption, and the addition was completed Quickly stopper the saline plug and ventilate several times, inject ultra-dry DCM under ventilated state, react at room temperature for 2-3 h, and monitor the reaction process by TLC every 0.5 h. After the reaction is complete, add 100 mL of water and extract with DCM 50 mL/time until the water phase has no obvious color, combine the organic phase and wash with saturated brine for 3-4 times, dry the organic phase with anhydrous sodium sulfate and spin to dry the solvent, and perform column chromatography Separation and rapid elution with eluent DCM:EtOH=30:1 gave the red solid product T3MA (109 mg, 82%). ¹ H NMR (400MHz, CDCl ₃ , 298K), δ (TMS, ppm): 7.88-7.72 (m, 12H, -ArH), 7.65-7.55 (m, 3H, -ArH), 7.27 (s, 2H, - ArH), 6.73-6.53 (m, 12H, -ArH), 4.38 (t, J = 6.0Hz, 4H, -CH ₂ -), 4.19 (t, J = 6.4Hz, 2H, -CH ₂ -), 4.13 (t, J=6.3Hz, 4H, -CH ₂ -), 4.05(t, J=6.6Hz, 6H, -CH ₂ -), 3.84-3.69(m, 10H, -CH ₂ -), 3.45(q ,J=7.1Hz,4H,-CH ₂ -),3.35(t,J=7.8Hz,4H,-CH ₂ -),2.94(t,J=7.1Hz,4H,-CH ₂ -),2.66- 2.54(m, 6H, -CH ₂ -), 2.22(p, J=6.7Hz, 4H, -CH ₂ -), 1.91(p, J=6.5 Hz, 2H, -CH ₂ -), 1.69-1.51( m, 12H, -CH ₂ -), 1.51-1.34 (m, 10H, -CH ₂ -), 1.21 (t, J=7.0Hz, 6H, -CH ₃ ). ¹³ C NMR (100MHz, CDCl ₃ , 298K ), δ (ppm): 170.8, 170.3, 154.8, 151.2, 147.8, 147.2, 147.2, 143.9, 134.2, 134.1, 126.4, 126.0, 122.3, 117.3, 116.6, 111.7, 111.1, 109.2, 68.6 ,64.8,64.7,51.2 ,50.5,47.2,45.4,33.6,32.9,28.8,28.4,28.4,27.5,26.7,25.7,25.7,25.6,21.8,12.4.

Synthesis of _N2N3 :

The reaction formula is:

The specific steps are:

Weigh the acceptor nitroaniline (1.0eq) and put it into the reaction tube, dissolve it completely with as little fluoroboric acid as possible, and stir the reaction tube at 0°C, and after about 10 minutes, dissolve the NaNO dissolved in as little ice water as possible _2. Drop the solution into the reaction tube, and continue stirring at 0°C for 3-4h after dropping. Donor aniline (1.1 eq) dissolved in ice-THF was dropped into the reaction tube, and the reaction was continued at 0° C. for 3-4 h after the dropping, and the reaction process was monitored by TLC. After the reaction was completed, 100 mL of water was added to quench and extracted with DCM. The organic phases were combined and dried over anhydrous sodium sulfate, and then the solvent was removed by rotary evaporation. The crude product was separated by column chromatography to obtain a red solid product. ¹ H NMR(400MHz,CDCl ₃ ,298K),δ(TMS,ppm):8.39-8.25(m,2H,-ArH),7.99-7.87(m,4H,-ArH),6.87-6.75(m,2H , -ArH), 3.80-3.64(m, 4H, -CH ₂ -), 3.59(t, J=6.0Hz, 4H, -CH ₂ -). ¹³ C NMR (100MHz, CDCl ₃ , 298K), δ( ppm): 156.4, 150.0, 147.7, 144.5, 126.2, 124.7, 122.8, 111.9, 50.7, 48.8.

The preparation steps of the second-order nonlinear optical polymer material are as follows:

Take T3MA and _N2N3 of corresponding mass according to stoichiometric ratio and use THF as a solvent to configure a solution with a concentration of 25mg/mL (generally controlled concentration is 20-40mg/mL, preferably 25mg/mL in this embodiment), using 0.22 Micron filter membrane to filter the prepared solution. Place the ITO glass on the stage of the glue homogenizer, with the non-conductive side facing up, and drop 80 microliters of the solution on this surface with a pipette gun, and start to homogenize the glue quickly after dropping. Coating process: the first stage rotates at 1000rpm and takes 18s; the second stage rotates at 1500rpm and takes 60s with no time interval between the two stages. A uniform transparent film was thus obtained. One group was dried in vacuum at 25°C for 8 hours and then polarized, and the other group was polarized after being heated at 110°C for 1 hour after film formation. The polarization was performed on a 1064 nm laser system using the original The second harmonic generation (SHG) test system was used to polarize and test the obtained film. The corona polarization conditions are: 7000V high-voltage DC power supply, and the polarization distance is 8mm. .

The second-order nonlinear optical effect test process is as follows:

On a 1064nm laser system, the obtained thin films were tested by an in-situ second harmonic generation (SHG) test system. The corona polarization conditions are: 7000V high-voltage DC power supply, and the polarization distance is 8mm. The test process is as follows: the polarization curve and the optimum polarization temperature T _e of the film are tested by applying voltage and heating at a rate of 5°C/min, and the temperature is raised from room temperature to the optimum polarization temperature (the optimum polarization temperature is generally ≤150°C, according to It needs to be heated to the corresponding optimal polarization temperature); keep the polarization voltage, the temperature drops to room temperature, then remove the polarization voltage and then increase the temperature to test its depolarization curve and decay temperature T _80% , the heating rate is 5℃/ min. Parallel conditions: test at least 3 films for the same sample, take at least 3 sets of values for each film, and sample the thickness of the same film at least 6 times.

The test results are shown in Table 1:

^a optimal polarization temperature; ^b film thickness; ^c UV-Vis maximum absorption wavelength of the film; ^d NLO coefficient measured by SHG; ^e second-order nonlinear optical effect of the non-resonant enhanced part calculated by dual energy and model; ^f Order parameter Φ=1-A ₁ /A ₀ , where A ₁ and A ₀ are respectively the absorbance of the film at λ _max after polarization and before polarization; the temperature when ^g d ₃₃ decays to 80% of the initial value.

From the data in Table 1 above, compared with the preheated film (T3MA/N2N ₃ preheated), the non-preheated film (T3MA/N2N ₃ preheated) shows a higher d ₃₃ value, and the difference in T _80% is smaller, indicating that the two The stability is basically the same. That is, the thermal crosslinking is also completely carried out during the in situ polarization process. Comparing the optimal polarization temperature and order parameters of the two, it can also be found that the unheated group is more easily polarized and shows a better polarization effect.

Example 2:

Synthesis of T3MA:

With embodiment 1.

Synthesis of _S2N3 :

The reaction formula is:

The specific steps are:

Weigh the acceptor sulfone aniline (1.0eq) and put it into the reaction tube, dissolve it completely with as little fluoroboric acid as possible, stir the reaction tube at 0°C, and after about 10 minutes, dissolve the NaNO dissolved in as little ice water as possible _2. Drop the solution into the reaction tube, and continue stirring at 0°C for 3-4h after dropping. Donor aniline (1.1 eq) dissolved in ice-THF was dropped into the reaction tube, and the reaction was continued at 0° C. for 3-4 h after the dropping, and the reaction process was monitored by TLC. After the reaction was completed, 100 mL of water was added to quench and extracted with DCM. The organic phases were combined and dried over anhydrous sodium sulfate, and then the solvent was removed by rotary evaporation. The crude product was separated by column chromatography to obtain a red solid product. ¹ H NMR (400MHz, CDCl ₃ , 298K), δ(TMS, ppm): 8.09-7.83(m, 6H, -ArH), 6.81(d, J=8.8Hz, 2H, -ArH), 3.71(t, J=6.0Hz, 4H, -CH ₂ -), 3.58(t, J=6.0Hz, 4H, -CH ₂ -), 3.15(q, J=7.2Hz, 2H, -CH ₂ -), 1.30(t , J＝ 7.2Hz, 3H, -CH ₃ ). ¹³ C NMR (100MHz, CDCl ₃ , 298K), δ(ppm): 156.1, 149.7, 144.4, 138.2, 129.3, 126.0, 122.8, 111.8, 50.7, 50.7, 48.7,7.4.

The preparation steps of the second-order nonlinear optical polymer material and the second-order nonlinear optical effect test process are the same as in Example 1, and the results are shown in Table 2:

^a optimal polarization temperature; ^b film thickness; ^c UV-Vis maximum absorption wavelength of the film; ^d NLO coefficient measured by SHG; ^e second-order nonlinear optical effect of the non-resonant enhanced part calculated by dual energy and model; ^f Order parameter Φ=1-A ₁ /A ₀ , where A ₁ and A ₀ are respectively the absorbance of the film at λ _max after polarization and before polarization; the temperature when ^g d ₃₃ decays to 80% of the initial value.

The information obtained from the data in Table 2 is basically consistent with that of Example 1. By comparing the two examples, it is found that the addition of S2N ₃ slightly increases the d ₃₃ value and T _80% of the film. This demonstrates the superiority of the spaced chromophore strategy.

Example 3:

Synthesis of T3MA:

With embodiment 1.

Synthesis of _T2N3 :

The reaction formula is:

The specific steps are:

A magnet was placed in the Schlenk bottle, and compound N2N ₃ (300.0 mg, 0.79 mmol), compound 4 (982.0 mg, 2.37 mmol), CuSO ₄ 5H ₂ O (78.9 mg, 0.32 mmol), VcNa (468.9 mg, 2.37mmol), after weighing, quickly stopper the saline stopper and ventilate several times; take another eggplant-shaped bottle, add 20mL tetrahydrofuran and 3mL water into it, and put it under ultrasonic exhaust for 10-15min, after the ultrasonic stop, under the ventilation state Take 12 mL of the mixed solvent and inject it into a Schlenk bottle in a ventilated state, react at 30° C. for 3-4 h, and monitor the progress of the reaction by TLC. After the reaction is completed, add 100 mL of water to the reaction solution and add 1,4,7,10-tetraazacyclododecane to complex the copper ions in it and extract 3-4 times with 50 mL of DCM each time, combine the organic phases with saturated salt After washing with water for 3-4 times, it was dried with anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The crude product was subjected to column chromatography to obtain the red solid product T2Cl (697 mg, 73%). ¹ H NMR (400MHz, CDCl ₃ , 298K), δ(TMS, ppm): 8.26(d, J=8.8Hz, 2H), 7.90-7.81(m, 8H), 7.79-7.74(m, 4H), 7.63 (d, J=8.8Hz, 2H), 7.24(s, 2H), 6.79-6.69(m, 4H), 6.59-6.49(m, 2H), 4.38(t, J=6.0Hz, 4H), 4.13( t,J=6.4Hz,4H),3.82-3.62(m,12H),3.53(q,J=7.2Hz,4H),2.96(t,J=7.2Hz,4H),2.24(p,J=6.8 Hz,4H),1.24(t,J=6.8Hz,6H).

Weigh T2Cl (500.0mg, 0.41mmol) in the reaction flask, put it into a magnet, add DMF 5mL and stir at room temperature; weigh _NaN3 (58.6mg, 0.90mmol) and add it to the reaction flask in batches, and heat up to 70 °C, stoppered the bottle mouth and reacted for 5-6 hours in a drying tube, and monitored the reaction progress by TLC. After the reaction is completed, add 100 mL of water and extract with DCM 50 mL/time until the water phase has no obvious color, combine the organic phases and wash with saturated brine for 3-4 times, dry the organic phase with anhydrous sodium sulfate and spin dry, and the crude product is passed through the column Chromatography, fast elution with eluent DCM:EA=10:1 gave red solid product T2N ₃ (471mg, 94%). ¹ HNMR (400MHz, CDCl ₃ , 298K), δ (TMS, ppm): 8.30-8.21 (m, 2H), 7.90-7.79 (m, 8H, -ArH), 7.78-7.72 (m, 4H, -ArH) ,7.62(d,J=8.8Hz,2H,-ArH),7.23(s,2H,-ArH),6.76(d,J=8.4Hz,4H,-ArH),6.54(d,J=8.4Hz, 2H, -ArH), 4.38(s, 4H, -CH ₂ -), 4.13(t, J=6.0Hz, 4H, -CH ₂ -), 3.73(t, J=6.0Hz, 4H, -CH ₂ - ), 3.64-3.46(m, 12H, -CH ₂ -), 2.96(t, J=7.2Hz, 4H, -CH ₂ -), 2.24(p, J=6.8Hz, 4H, -CH ₂ -), 1.25 (t, J=6.8Hz, 6H, -CH ₃ ). ¹³ C NMR (100MHz, CDCl ₃ , 298 K), δ (ppm): 155.0, 150.6, 148.1, 147.2, 126.3, 126.0, 124.6, 122.9, 122.4, 117.4, 116.6, 111.7, 111.5, 109.22, 68.5, 51.2, 49.6, 48.9, 47.3, 45.9, 28.3, 21.8, 12.3.

The preparation steps of the second-order nonlinear optical polymer material and the second-order nonlinear optical effect test process are the same as in Example 1, and the results are shown in Table 3:

^a optimal polarization temperature; ^b film thickness; ^c UV-Vis maximum absorption wavelength of the film; ^d NLO coefficient measured by SHG; ^e second-order nonlinear optical effect of the non-resonant enhanced part calculated by dual energy and model; ^f Order parameter Φ=1-A ₁ /A ₀ , where A ₁ and A ₀ are respectively the absorbance of the film at λ _max after polarization and before polarization; the temperature when ^g d ₃₃ decays to 80% of the initial value.

Similarly, the information obtained from the data in Table 3 is basically consistent with that of Examples 1 and 2. By comparing the three examples, it is found that the addition of T2N ₃ does not make the film show better second-order nonlinear optical properties.

Example 4:

Synthesis of T3MA:

With embodiment 1.

Synthesis of TS2N ₃ :

The reaction formula is:

The specific steps are:

A magnet was placed in the Schlenk bottle, and compound S2N ₃ (300.0mg, 0.7mmol), compound 5 (971.0mg, 2.1mmol), CuSO ₄ 5H ₂ O (70.0mg, 0.28mmol), VcNa (416.0 mg, 2.1 mmol), stoppered with saline immediately after weighing, and pumped for ventilation several times; take another eggplant-shaped bottle, add 20 mL of tetrahydrofuran and 3 mL of water into it, and put it under ultrasonic exhaust for 10-15 minutes, and the state of ventilation after the ultrasonic stop Take 13 mL of the mixed solvent and inject it into a Schlenk bottle under ventilated state, and react at 30° C. for 3-4 hours and monitor by TLC midway. After the reaction was completed, 100 mL of water was added to the reaction liquid, extracted 3-4 times each time with 50 mL of DCM, the obtained organic phase was washed 3-4 times with saturated brine, dried with anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. Column chromatography gave the product TS2Br (738 mg, 78%) as a red solid. ¹ H NMR(400MHz,CDCl ₃ , 298K),δ(TMS,ppm):8.05-7.97(m,4H),7.96-7.88(m,14H),7.22(s,2H),6.78-6.69(m, 6H), 4.44(t, J=6.0Hz, 4H), 3.80(t, J=7.6Hz, 4H), 3.73(t, J=6.0Hz, 4H), 3.58-3.47(m, 8H), 3.21- 3.11(m,6H),2.83(t,J=7.2Hz,4H),2.14-2.04(m,4H),1.32-1.25(m,9H).

Weigh TS2Br (500.0mg, 0.37mmol) in the reaction flask, place a magnet, add DMF and stir at room temperature; weigh NaN ₃ (52.7mg, 0.81mmol) and add it to the reaction flask in batches, and heat up to 70°C after adding , stoppered the bottle and reacted for 5-6h in a drying tube, and monitored the progress of the reaction by TLC. After the reaction was completed, add 100 mL of water to the reaction bottle and extract with DCM 50 mL/time until the water phase has no obvious color. After combining the organic phases, wash them with saturated brine for 3-4 times, dry the organic phases with anhydrous sodium sulfate and spin them to dryness. The product was subjected to column chromatography and quickly eluted with the eluent DCM:EA=10:1 to obtain the red solid product TS2N ₃ (420 mg, 89%). ¹ H NMR(400MHz,CDCl ₃ ,298K),δ(TMS,ppm):8.03-7.96(m,4H,-ArH), 7.96-7.86(m,14H,-ArH),7.22(s,2H,- ArH), 6.80-6.74(m, 4H, -ArH), 6.74-6.68(m, 2H, -ArH), 4.43(t, J=6.0Hz, 4H, -CH ₂ -), 3.73(t, J= 6.0Hz, 4H, -CH ₂ -), 3.64-3.50(m, 12H, -CH ₂ -), 3.20-3.11(m, 6H, -CH ₂ -), 2.82(t, J＝7.2Hz, 4H, -CH ₂ -),2.13-2.02(m,4H,-CH ₂ -),1.34-1.22(m, 9H,-CH ₃ ). ¹³ C NMR(100MHz,CDCl ₃ ,298K),δ(ppm): 156.3, 155.9, 150.7, 146.3, 143.8, 138.3, 129.3, 129.0, 126.2, 123.0, 122.8, 122.3, 112.0, 111.5, 47.2, 45.9, 23.7, 22.6, 12.3, 7.5.

The preparation steps of the second-order nonlinear optical polymer material and the second-order nonlinear optical effect test process are the same as in Example 1, and the results are shown in Table 4:

a optimal polarization temperature; ^b film thickness; ^c UV-Vis maximum absorption wavelength of the film; ^d NLO coefficient measured by SHG; ^e second-order nonlinear optical effect of the non-resonant enhanced part calculated by dual energy and model; ^f Order parameter Φ=1-A ₁ /A ₀ , where A ₁ and A ₀ are respectively the absorbance of the film at λ _max after polarization and before polarization; the temperature when ^g d ₃₃ decays to 80% of the initial value.

The information obtained from the data in the table is basically consistent with Examples 1, 2, and 3. By comparing the four examples, it is found that the addition of TS2N ₃ greatly improves the d ₃₃ value without changing the stability of the film. And d _33(∞) reached the highest value based on azobenzene chromophore polymers.

Fig. 1 shows the infrared spectrum (1a) of each doping monomer in embodiment 1-4 and the infrared spectrum (1b) before and after heating of the doped film, proves the above-mentioned in-situ thermal crosslinking process with infrared spectrum: from Fig. 1 ( a) It can be seen that T3MA shows obvious maleimide double bond carbon-hydrogen characteristic peaks, while T2N ₃ and TS2N ₃ show obvious azide characteristic stretching vibration peaks. After the doping of the two components, as shown in Figure 1(b), the above two groups of characteristic peaks remained before heating, but disappeared after heating, indicating that the crosslinking reaction between azide and maleimide occurred during the heating process. Figure 2 shows the solubility test of the polarized products of Examples 1-4. It can be seen from the figure that the polymer network structure formed by crosslinking shows obvious solvent resistance compared with that before heating.

Example 5:

This embodiment involves the doping of FTC and azo chromophores, and the physical quantities related to the maximum absorption wavelength, such as the maximum absorption wavelength, order parameter and d _{33 (∞)} of the film, are of little significance and are not summarized.

Synthesis of F2MA:

Put magnets in the Schlenk bottle, weigh F2OH (495.0mg, 1.0eq), maleimide propionic acid (314.5mg, 2.5eq), EDC (336.2mg, 2.3eq), DPTS (95.3mg, 0.4eq ) after weighing, dissolved in dry dichloromethane, plugged the drying tube and reacted in the dark at room temperature. After the reaction is complete, add 100 mL of water and extract with DCM 50 mL/time until the water phase has no obvious color, combine the organic phase and wash with saturated brine for 3-4 times, dry the organic phase with anhydrous sodium sulfate and spin to dry the solvent, and perform column chromatography Separation and rapid elution with eluent DCM:EtOH=30:1 gave red solid product F2MA (651.0 mg, 90%). ¹ H NMR (400MHz, CDCl ₃ , 298K) δ9.05 (d, J = 15.6Hz, 1H), 7.92 (d, J = 1.2Hz, 1H), 7.40 (d, J = 8.4Hz, 2H), 7.26 (s,1H),7.16-6.91(m,2H),6.75-6.64(m,7H),4.44(t,J=7.2Hz,2H),4.26(t,J=6.4Hz,2H),4.07( t,J=6.4Hz,2H),3.82(td,J=7.2,1.2Hz,4H),3.61(t,J=6.4Hz,2H), 3.46(q,J=7.2Hz,2H),2.64( td,J＝7.2,3.2Hz,4H),2.05-1.93(m,2H),1.83(s,6H),1.61(d,J＝2.4Hz,2H),1.47–1.33(m,J＝3.2, 2.4Hz, 4H), 1.21(t, J=7.2Hz, 3H).

Synthesis of _N2N3 :

With embodiment 1.

The preparation steps of the second-order nonlinear optical polymer material and the test process of the second-order nonlinear optical effect are the same as in Example 1, and the results are shown in Table 5.

^a Optimum polarization temperature; ^b film thickness; ^c NLO coefficient measured by SHG; ^{d d} The temperature when the value of d ₃₃ decays to 80% of the initial value.

It can be seen from the data in the table that although the d ₃₃ value of the FTC-doped film is not high, its T _80% is as high as 143°C, which is a huge improvement compared with the pure azo chromophore.

Embodiment 6:

This embodiment involves the doping of FTC and azo chromophores, and the physical quantities related to the maximum absorption wavelength, such as the maximum absorption wavelength, order parameter and d _{33 (∞)} of the film, are of little significance and are not summarized.

Synthesis of F2MA:

With embodiment 5.

Synthesis of _S2N3 :

With embodiment 2.

The preparation steps of the second-order nonlinear optical polymer material and the second-order nonlinear optical effect test process are the same as in Example 1, and the results are shown in Table 6.

^a Optimum polarization temperature; ^b film thickness; ^c NLO coefficient measured by SHG; ^{d d} The temperature when the value of d ₃₃ decays to 80% of the initial value.

It can be seen from the data in the table that the d ₃₃ value of the doped film is still not high, but it has been improved compared with Example 5, and its T _80% is maintained at 143°C, which is a huge improvement compared with the pure azo chromophore.

At the same time, the corresponding second-order nonlinear optical performance test was carried out on the doped monomers of Examples 1-4, and the results are shown in Table 7:

The data results in Table 7 show that the d ₃₃ and T _80% values of the non-preheated film are significantly improved compared with all monomers, reflecting the advantages of in-situ polarization thermal crosslinking.

The above description is only a preferred embodiment of the present invention, and of course the scope of rights of the present invention cannot be limited by this. It should be pointed out that for those of ordinary skill in the art, they can also Several improvements and changes are made, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims (7)

1. A method for constructing a second-order nonlinear optical polymer material by in-situ thermal crosslinking reaction is characterized by comprising the following steps: preparing a second-order nonlinear optical polymer network structure by taking a maleimide functionalized chromophore and an azide functionalized chromophore as thermal crosslinking monomers:

，

wherein MA is a maleimide functional group; r is R ₁ And R is ₂ Are second-order nonlinear optical molecules; m is maleimide functional group in R ₁ Number of functionalization on the molecule; n is-N ₃ Functional group at R ₂ Number of functionalization on the molecule;

the R is ₁ Any one selected from azo chromophores, R ₂ Any one selected from azo chromophore or FTC chromophoreOr R is the same or different ₂ Any one selected from azo chromophores, R ₁ Any one selected from azo chromophore and FTC chromophore can be the same or different;

the m is more than 2, n is more than or equal to 2, or m is more than or equal to 2, n is more than or equal to 2.

2. The method for constructing a second order nonlinear optical polymer material by in-situ thermal crosslinking reaction according to claim 1, wherein the method comprises the following steps: the R is ₁ ，R ₂ Is a single chromophore molecule or a multichromophore molecule.

3. The method for constructing a second order nonlinear optical polymer material by in-situ thermal crosslinking reaction according to claim 1, wherein the method comprises the following steps: the R is ₁ -mMA is prepared by esterification of a hydroxyl-containing chromophore molecule with a maleimide alkyl carboxylic acid.

4. The method for constructing a second order nonlinear optical polymer material by in-situ thermal crosslinking reaction according to claim 1, wherein the method comprises the following steps: the R is ₂ -nN ₃ The preparation is carried out by substituting halogenated chromophore molecule or p-toluenesulfonate-containing chromophore molecule with azide reagent.

5. The method for constructing a second order nonlinear optical polymer material by in-situ thermal crosslinking reaction according to claim 1, wherein the method comprises the following steps: subjecting the R to ₁ -mMA and R ₂ -nN ₃ Dissolving in a solvent to prepare a solution, coating the solution on the surface of a conductive substrate, drying to form a film, and polarizing at a certain temperature to obtain the second-order nonlinear optical polymer material.

6. The method for constructing a second order nonlinear optical polymer material by in situ thermal crosslinking reaction according to claim 5, wherein the method comprises the following steps: the solvent is any one of tetrahydrofuran, dichloromethane, chloroform and acetone, R is selected from the group consisting of ₁ -mMA and R ₂ -nN ₃ According to the stoichiometric ratio of the chemical reactionsMixing and preparing into solution with total concentration of 20-40 mg/mL.

7. The method for constructing a second order nonlinear optical polymer material by in situ thermal crosslinking reaction according to claim 5, wherein the method comprises the following steps: the temperature of the polarization process is 25-150 DEG C ^o C。