Determination of the glass transition temperature of photorefractive polymer composites from photoconductivity measurements

Abstract

A method to determine the glass transition temperature (Tg) of photorefractive (PR) polymer composites, based on photoconductivity measurements, is proposed. The composite Tg is identified as the temperature at which a clear change in slope in the Arrhenius plot representation of the photoconductivity is obtained. We demonstrate that for PR polymers, this method is more appropriate than the one generally used, based on differential scanning calorimetry (DSC). For PR composites based on the hole transporting polymer poly(N -vinylcarbazole), the Tg value determined from photoconductivity data is around 30 °C higher than that obtained by DSC. © 2008 American Institute of Physics.