Electro-optical and pyroelectrical thermal analysis of novel nonlinear optical side-chain polymers with high thermal stability

Polymers containing nonlinear optical moieties were prepared on the basis of maleic anhydride copolymers. Azo dyes such as Disperse Red 1 (DR 1) were attached to the polymer backbones via esterification, amidization, or imidization. Optimal poling conditions for the side-chain polymers were determined by means of thermal analysis. After electrode poling with a bias voltage of 200 V at a temperature of 185°C, the spin-coated samples were slowly cooled down to room temperature with the poling field still applied. The thermal stabilities of the poled polymer films were measured by means of electro-optical (EOTA) and pyroelectrical (PTA) thermal analysis and compared to the respective responses of DR 1/polymethylmethacrylate (PMMA) guest/host polymer samples. Both experimental techniques (EOTA and PTA) will be discussed in some detail together with the experimental results. An electro-optical r₃₃ coefficient of approximately 6 pm/V was achieved at a wavelength of 780 nm for one of the side-chain polymers, and the electro-optical activity decreased only at temperatures above 150°C.