Synthesis of Novel Y-Type Nonlinear Optical Polyurethane Containing Tricyanovinylthiophene with High Thermal Stability of Dipole Alignment

Abstract

A novel Y-type polyurethane 7 containing 1-(2,4-dioxyethoxy)phenyl-2-{5-(1,2,2-tricyanovinyl)-2-thiophenyl)}ethenyl groups as nonlinear optical (NLO)-chromophores, which are components of the polymer backbones, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It showed a thermal stability up to 280°C in TGA thermogram and the T g value obtained from DSC thermogram was around 163°C. The second harmonic generation (SHG) coefficient (d 33 ) of poled polymer film at 1560 nm fundamental wavelength was around 3.72 × 10−9 esu. The dipole alignment exhibited a thermal stability up to near T g , and there was no SHG decay below 150°C due to the partial main-chain character of the polymer structure, which is acceptable for nonlinear optical device applications.