Studies on thermo-optic property of chitosan-alizarin yellow GG complex: a direction for devices for biomedical applications

The optical parameters including the refractive index (n) and thermo-optic coefficient, TOC (dn/dT), the dielectric constant (epsilon) and its variation with temperature, and the thermal volume expansion coefficient (beta) and its variation with temperature of chitosan-alizarin yellow GG (CS-AY GG) complex were examined. The dn/dT and epsilon-values for the polymer derivative were in the range -2.5 x 10(-4) to 1.2 x 10(-4 degrees)C(-1) and 2.2 to 2.3, respectively. The dn/dT values were larger than that of inorganic glasses such as zinc silicate glass (5.5 x 10(-6 degrees)C(-1)) and borosilicate glass (4.1 x 10(-6 degrees)C(-1)) and were larger than that of organic polymers such as polystyrene (-1.23 x 10(-4 degrees)C(-1)) and PMMA (-1.20 x 10(-4 degrees)C(-1)). The epsilon-values are lower than optically estimated epsilon-values of conventional polymer (3.00), aliphatic polyimide (2.5) and semi-aromatic polyamide (2.83). The obtained results of chitosan derivative are expected to be useful for optical switching and optical waveguide areas for devices of biomedical applications.