Synthesis and characterization of a novel nonlinear optical polyurethane polymer

A cross-linked polyurethane with a novel nonlinear optical (NLO) chromophore [2-(4'-N,N-dihydroxyethylphenylazo)-3,5-dinitrothiophene] covalently incorporated for second-order optical nonlinearity was developed. High optical-quality films can be obtained from the prepared polymer. Resonance-enhanced second-harmonic coefficient (d(33)) Of 66 pm V-1 at 1.064 mum fundamental wavelength of the poled films was obtained. Test on temporal stability shows that when the films were kept in an oven at 100 degreesC for 1000 h in air, 75% of the NLO signal still remained. (C) 2001 Elsevier Science Ltd. All rights reserved.