ABSTRACT
A novel X-type polyester containing 4-(2′,2′-dicyanovinyl)-5-nitrocatecholic groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. The polyester is soluble in common organic solvents such as N,N-dimethylformamide and acetone. It shows a thermal stability up to 300°C from thermogravimetric analysis with glass-transition temperature obtained from differential scanning calorimetry of near 105°C. The second harmonic generation (SHG) coefficient (d33) of a poled polymer film at the 1064 nm fundamental wavelength is 5.31 × 10−9 esu. The dipole alignment exhibits a thermal stability even at 5°C higher than glass-transition temperature (Tg), and no significant SHG decay is observed below 110°C due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.
Funding
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2015R1D1A1A09058972).