Electroluminescence cells with H[3,4-b] quinoline layers are promising devices for a blue light emitting EL diode. This work measured the optical reflectance as a function of temperature in copolymers PAQ layers deposited on Si crystalline substrate. Using the extended Cauchy dispersion model of the film refractive index we determined the thermo-optical coefficients for quinoline layers in the temperature range of 76–333K from combined ellipsometric and spectrofotometric studies. The obtained values of thermo-optical coefficients of thin PAQ film, were negative and ranged in 5–10×10 −4 [1/K].