Thermo-optic coefficients (TOC) of inorganic-organic hybrid glass (HYBRIMER) films prepared by sol-gel process of organoalkylsilanes were measured using the prism coupler equipped with auto-controlled hot stage. The spin coated HYBRIMER films composing of silica and methacrylate networks were fabricated for the measurement. Their TOCs are negative and as high as the order of 10(-4), which are comparable to those of optical polymers. It was found that composition of the films, formation of organic network and addition of other elements in the HYBRIMER affect TOCs of the films.