Synthesis and Properties of Novel Y-type Nonlinear Optical Polyester Containing Cyanovinylthiophene with Enhanced Thermal Stability of Second Harmonic Generation

Abstract

New Y-type polyester (3) containing nitrophenylazoresorcinoxy groups as NLO chromophores, which are components of the polymer backbone, was prepared and characterized. Polyester 3 is soluble in common organic solvents such as N,N-dimethylformamide and acetone. It shows a thermal stability up to 240 o C in thermogravimetric analysis with glass-transition temperature (T g ) obtained from differential scanning calorimetry near 116 o C. The second harmonic generation (SHG) coefficient (d 33 ) of poled polymer film at the 1064 nm fundamental wavelength is around 4.63 × 10 −9 esu. The dipole alignment exhibits a thermal stability even at 4 o C higher than T g , and there is no SHG decay below 120 o C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.