Measurement of thermal diffusivity for polymer film by flash radiometry

Abstract
A new method to determine the thermal diffusivity of polymer film by flash radiometry is presented. The transient infrared radiation from the sample surface was measured after the sample film was heated by a short-duration pulsed light. The thermal diffusivity was determined by fitting the transient infrared signal to the theoretical curve of a one-dimensional heat diffusion model. The transient infrared signal of polymethylmethacrylate (PMMA) film could be well fitted by the theoretical curve using appropriate thermal diffusivity in the wide temperature range between 100 K and near the softening point of PMMA. The temperature dependence of thermal diffusivity of PMMA film showed that the thermal diffusivity sensitively reflects the molecular motion of polymer chain.