Synthesis and Nonlinear Optical Properties of Novel Y-type Polyester Containing Nitrophenylazoresorcinoxy Group

Abstract

A new Y-type polyester (3) containing nitrophenylazoresorcinoxy groups as NLO chromophores, which are components of the polymer backbone was prepared. Polyester 3 is soluble in common organic solvents such as N,N-dimethylformamide and acetone. It shows a thermal stability up to 240 C from thermogravimetric analysis with glass-transition temperature (T g ) obtained from differential scanning calorimetry near 116 C. The second harmonic generation (SHG) coefficient (d 33 ) of poled polymer films at the 1064 nm fundamental wavelength is around 4.63 Â 10 À9 esu. The dipole alignment exhibits a thermal stability even at 4 C higher than T g , and no SHG decay was observed below 120 C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.