Synthesis and second-order nonlinear optical properties of tricyanovinylated polybenzoxazole

Abstract

We have developed the second-order nonlinear optically (NLO) active polybenzoxazole as a new thermally stable NLO polymeric system. This polybenzoxazole was synthesized by direct polycondensation of diacid monomer containing N-phenyl pendant with 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane using phosphorus pentoxide/methanesulfonic acid as a condensing agent and solvent, followed by a post-substitution of tricyanovinyl group. The resultant polybenzoxazole had a glass transition temperature of about 180 degrees C and an initial decomposition temperature of about 300 degrees C. Electro-optic coefficient of this polybenzoxazole film poled at 1.5 MV cm(-1) was 34 pm V-1 (at 633 nm), and its NLO activity was quite stable at 100 degrees C during long period.