Thermal diffusivity measurements in glass and Teflon using photopyroelectric signal spectral analysis and correlation techniques

Thermal diffusivity measurements in glass and Teflon are reported over the temperature range from 90 to 300 K. The results are obtained by multifrequency rear surface excitation combined with impulse response determination using correlation photopyroelectric techniques. A simple and versatile computer-based system performing generation of given excitation wave forms, data acquisition, and analysis is described. A one-dimensional model is proposed in order to explain the experimental results. (C) 1996 American Institute of Physics.