Synthesis and nonlinear optical properties of novel polyester containing dicyanovinylnitrocatecholic group

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 (T_g), 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.

KEYWORDS:

• Differential scanning calorimetry (DSC)
• dipole alignment
• NLO
• polyester
• SHG coefficient
• thermogravimetric analysis (TGA)

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).