Synthesis and nonlinear optical properties of novel Y-type polyurethane containing nitrothiazolylazoresorcinoxy groups with highly enhanced thermal stability of second harmonic generation

Novel Y-type polyurethane 4 containing 4-(5-nitro-2-thiazolylazo)resorcinoxy groups as nonlinear optical (NLO) chromophores, which are parts of the polymer main chains, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as N,N-dimethylformamide and dimethylsulfoxide. It shows thermal stability up to 280 degrees C as determined from thermogravimetric analysis with a glass transition temperature obtained from differential scanning calorimetry of about 126 degrees C. The second harmonic generation (SHG) coefficient (d(33)) of poled polymer film at 1064 nm fundamental wavelength is 3.78 pmV(-1). Polymer 4 exhibits thermal stability even at 4 degrees C higher than glass transition temperature, and no significant SHG decay is observed below 130 degrees C, which is acceptable for NLO device applications. (c) 2016 Society of Chemical Industry