Modeling Transient Heat Conduction and Radiative Transport in Semitransparent Media: A Tool for the Interpretation of Reflectivity Data

In this work the problem of interpretation of reflectivity data for semitransparent materials at high temperatures is addressed. A detailed analysis of the transient thermal response of a participating medium subjected to a pulse of finite energy is performed using a new method developed to solve the general equation of energy transfer for a conductive, absorbing, emitting, and scattering medium. The model, previously presented for a material with constant optical properties (Musella, Tschudi, Int J Thermophys 26:981, 2005), has been upgraded to encompass a much wider scenario where the thermophysical and optical properties are temperature dependent. This allows the study of the transient reflectivity of laser-heated samples where high heating rates and strong temperature gradients occur near the surface. Considerable differences of the reflectivity values for the same surface temperature calculated in the heating and cooling phases, both different from the corresponding values for an isothermal sample, are reported in accordance with experimental result