A new NLO polyurethane with a tricyanovinyl group

A new functionalized polyurethane structure with a heteroaromatic thiophene ring having a tricyanovinyl group in the polymer side chain was synthesized. The resulting polymer was soluble in N-methylpyrrolidinone and could be processed into good optical quality films by spin casting at ca. 100 °C. The second-order nonlinear coefficient, d33, was determined to be 51 pm/V from measuring the second harmonic generation (SHG) for a thin polymer film. The outstanding orientational stability of the aligned chromophores was observed up to about 150 °C, which originated from the rigid polymer backbone and the stabilizing function of the hydrogen bridges formed between the neighboring polyurethane chains.