A Hyperbranched Nonlinear Optical Polyester with Polar Chromophores

Abstract

Second-order nonlinear optical (NLO) polymeric materi-als have been recognized as the promising candidates for various photonic devices such as electro-optic modulators, optical switches and frequency doublers.1-5 These interests in polymers arise from their large NLO activities, low dielectric constants, excellent processability, high optical damage threshold, etc. Several strategies for making NLO polymer systems have been proposed. Those are side-chain polymers and main-chain polymers of one-dimensional types in which NLO active chromophores are incorporated either by attach-ing to an amorphous polymer, or into a polymer backbone.6-11 In addition, a 3-dimensional polymeric network structure with NLO chromophores can be obtained through thermally or photochemically induced crosslinking reactions.12,13 How-ever, the crosslinked systems have the problem of large opti-