Synthesis and Nonlinear Optical Properties of Novel Polyester with Enhanced Second Harmonic Generation Thermal Stability

Nonlinear optical (NLO) polymers received a great attention in recent years because of their potential applications in the field of electro-optic devices including ultrafast optical switches, high-speed optical modulators, and high-density optical data storage media.1-6 A potential NLO polymer has to be mecha-nically very strong and thermally stable with a high glass-tran-sition temperature (Tg). In the developments of NLO polymers for electro-optic device applications, stabilization of electrically induced dipole alignment is one of important criteria; in this context, two approaches have been proposed to minimize the randomization of dipole alignment, namely the use cross-link-ing method7-10 and the utilization of high Tg polymers such as polyimides.11-16 Various polyesters with NLO chromophores in the main chain17 or in side chain18-19 have been prepared and their properties studied. In general, main-chain NLO polymer