Synthesis and nonlinear optical properties of novel Y-type polyurethane containing tricyanovinylthiazole with enhanced thermal stability of second harmonic generation

• Published in: Journal of polymer science. Part A, Polymer chemistry Vol. 48; no. 5; pp. 1166 - 1172
• Main Authors: No, Hyo Jin, Jang, Han-Na, Jin Cho, You, Lee, Ju-Yeon
• Format: Journal Article
• Language: English
• Published: Wiley Subscription Services, Inc., A Wiley Company 01.03.2010
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.23875

A novel Y-type poly[iminocarbonyloxyethyl-5-methyl-4-{2-thiazolylazo-4-(1,2,2-tricyanovinyl)}resorcinoxyethyloxycarbonylimino-(3,3′-dimethoxy-4,4′-biphenylene)] 4 containing 5-methyl-4-{5-(1,2,2-tricyanovinyl)-2-thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. It showed a thermal stability up to 250 °C in thermogravimetric analysis thermogram and the glass-transition temperature (Tg) obtained from differential scanning calorimetry thermogram was around 118 °C. The second harmonic generation coefficient (d₃₃) of poled polymer films at 1560 nm fundamental wavelength was around 8.43 x 10⁻⁹ esu. The dipole alignment exhibited a thermal stability even at 12 °C higher than Tg, and there was no SHG decay below 130 °C due to the partial main-chain character of the polymer structure, which is acceptable for NLO device applications.