Synthesis and electro-optic properties of novel polyurethane containing the nitrophenylazoresorcinoxy group

A novel Y-type polyurethane (polyurethane 3) containing 4-(4-nitrophenylazo)resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 3 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. It shows thermal stability up to 270 degrees C from thermogravimetric analysis with a glass transition temperature obtained from differential scanning calorimetry of 102 degrees C. The second harmonic generation (SHG) coefficient (d(33)) of the poled polymer film at 1064 nm fundamental wavelength is 2.06 pm V-1. Polymer 3 exhibits thermal stability up to T-g, and no significant SHG decay is observed below 100 degrees C, which is acceptable for nonlinear optical device applications. (C) 2012 Society of Chemical Industry