Synthesis and Properties of Novel Polyurethane Containing Nitrophenylazocateeholic Group as NLO Chromophore

摘要

Nonlinear optical (NLO) polymers have been identified as strong candidates for use in photonic devices, including high-speed optical modulators, ultrafast optical switches and high-density optical data storage media. The promise of NLO polymers lies in their higher nonlinear optical activity, faster response time, and easy fabrication into electro-optic devices. In the developments of NLO polymers for electro-optic device applications, stabilization of electrically induced dipole alignment is one of important considerations; in this context, two approaches to minimize the randomization have been proposed, namely the use of cross-linked systems and the utilization of polymers with high glass transition temperature (T_g) such as polyimides. A polyurethane matrix forms extensive hydrogen bonding between urethane linkages, with increased rigidity preventing the relaxation of induced dipoles.