Electro-optic (EO) effect and thermo-optic (TO) effect are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point in waveguide components. TO coefficients of EO fluorinated polyimide films with side-chain azobenzene chromophore were measured by attenuated-total-reflection (ATR) technique at different temperatures with TE- and TM-polarized lights, respectively. It is found that the absolute values of TO coefficients increase with the increme