两类非线性光学性质稳定的交联极化聚合物

Two Novel Crosslinked Poled Polymers with Stable Second-Order Nonlinear Optical Properties

报道了两类新型含对硝基苯偶氮苯胺发色团的热交联型二阶非线性光学聚合物的合成和极化工艺。双端丙烯酸酯的分散红（ＤＲ）－１９热聚合生成交联型聚丙烯酸酯；双端苯酚封闭异氰酸酯端基的ＤＲ－１９与含多羟基的（丙烯酸－β－羟丙酯－ＤＲ－１－ＭＡ）共聚物反应生成交联聚氨酯。ＤＳＣ测得两者的玻璃化转变温度分别为１２５℃和１６０℃。旋转涂膜后在１６０℃电晕极化１ｈ可制得良好光学性质的极化膜。采用可见光吸收光谱测定了极化膜取向发色团的序参数及其取向的热稳定性，用一维刚性取向气体模型计算两类极化膜的二阶非线性光学极比系数Ｘ^（２）达１０^（－７）ｅｓｕ量级。其中交联聚氨酯极化膜有优异的取向稳定性，在１４０℃经２４０ｈ取向，序参数保持初值的９０％。

Two kinds of crosslinked polymers, containing 4( 4'-nitro-phenylazo) aniline chromophore groups were synthesized. Crosslinked polyacrylate was synthesized by polymerization of DR-19 diacrylate, whereas crosslinked polyurethane was obtained by the reaction between(β-hydroxyl propyl acrylate-DR-1 methacrylate)copolymer and phenol capped isocyanate terminated DR-19.The crosslinked polyacrylate and the crosslinked polyurethane exhibit glass transition temperatures at 125℃ and 160℃ respectively.Thin and transparent poled films of both crosslinked polymers were prepared by spin-coating, followed by thermal curing and corona poling at 160℃ for 1 h. The second-order nonlinear optical properties of the poled films were studied by visible light absorbance measurement according to one dimensional rigid oriented gas model.A long term stability of the dipole alignment at 140℃ for the crosslinked polyurethane was demonstrated.