Kou HG, Shi WF (2004) Photorefractivity of hyperbranched polyisophthalate endeapped with pendant carbazolyl and azobenzene groups. European Polymer Journal 40(7), 1337-1342. [In English]

Web link:http://dx.doi.org/10.1016/j.eurpolymj.2004.02.017

Keywords:

photorefractive effect, hyperbranched polyisophthalate, electro-optic, coefficient, two-beam couple coefficient, polymer composites, performance, chromophore, gratings, gain

Abstract: A novel hyperbranched polyisophthalate containing pendant carbazolyl and azobenzene groups at the terminals was synthesized, and its photo refractivity has also been evaluated by the effective electro-optic (EO) coefficient, two-beam couple (TBC) coefficient, diffraction efficiency and photorefractive (PR) response time. This PR polymer has a low glass transition temperature of 21 degreesC without any extra plasticizer added, which provides a necessary free volume for EO chromophore reorientation during the recording process at room temperature. The obtained PR film exhibited an effective EO coefficient of 30 pm V-1, a TBC coefficient of 59 cm(-1), a diffraction efficiency of 17%, and a modulation index of 1.67 x 10(-3) at the wavelength of 632.8 nm with an applied electric field of 80 V mum(-1) at room temperature. The TBC coefficient was found to be beam-intensity dependent, compared with what is found in inorganic crystals. Moreover, a fast PR response time of 10 ms was deduced at an erasing beam intensity of 1.0 Wcm(-2). (C) 2004 Elsevier Ltd. All rights reserved.