Synthesis and Nonlinear Optical Properties of a Novel Polyester Containing Tricyanovinylthienyl Group

Abstract

A novel T-type polyester (7) containing 1-(2,5-dioxyphenyl)-2-{5-(1,2,2-tricyanovinyl)-2-thienyl}ethene groups as NLO-chromophores was synthesized and characterized. Polymer 7 was soluble in common organic solvents such as DMF and DMSO. It showed thermal stability up to 300°C in TGA with T _g value obtained from DSC near 113°C. The second harmonic generation (SHG) coefficient (d ₃₃ ) of poled polymer film at the 1560 nm fundamental wavelength was around 4.42 × 10⁻⁹ esu. The dipole alignment exhibited a greater thermal stability even at 10°C higher than T _g , and there was no SHG decay below 125°C due to the partial main-chain character of the polymer structure, which is acceptable for nonlinear optical device applications.

Keywords:

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

Acknowledgements

This research was supported by Basic Science Research Program Through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2009-0070572).

Notes

^a Polymer film after poling.

^b SHG coefficients (d ₃₃) were derived from the analysis of measured Maker-fringes [18].

^c Order parameter Φ = 1−A₁/A₀, where A₀ and A₁ are the absorbances of the polymer film before and after corona poling, respectively.

^d Film thickness was determined by the optical transmission technique [17].