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

Abstract

The optical parameters including the refractive index (n) and thermo-optic coefficient, TOC (dn/dT), the dielectric constant (ε) and its variation with temperature, and the thermal volume expansion coefficient (β) and its variation with temperature of chitosan-alizarin yellow GG (CS-AY GG) complex were examined. The dn/dT and ε-values for the polymer derivative were in the range -2.5 × 10-4 to 1.2 × 10-4°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 × 10-6°C-1) and borosilicate glass (4.1 × 10-6°C-1) and were larger than that of organic polymers such as polystyrene (-1.23 × 10-4°C-1) and PMMA (-1.20 × 10-4°C-1). The ε-values are lower than optically estimated ε-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.