HIGH PHOTOREFRACTIVE PERFORMANCE OF LOW GLASS-TRANSITION-TEMPERATURE POLYMERIC COMPOSITE DOPED WITH BIFUNCTIONAL CHROMOPHORE

We report a novel optimized nonlinear optical chromophore, butoxyl-2,5 -dimethyl-4-(4'-nitrophenyl-azo)benzene (BDMNPAB), that acts effective ly as both electro-optic chromophore and plasticizer in a low glass-tr ansition-temperature photorefractive polymeric composite. In the polym eric composite of BDMNPAB:poly(N-vinylcarbazole) (PVK):2,4,7-trinitro- 9-fluorenone in a weight ratio of 44.55:1, the glass transition temper ature was lowered to 43 degrees C. Two-beam coupling gain as high as 1 95 cm(-1) and an index grating amplitude of about 4.3 x 10(-3) were ob tained. Furthermore, high solubility of the dye in PVK and high stabil ity of the photorefractive composite were also exhibited.