A theory for time-resolved photothermal spectroscopy is proposed for <i>in situ</i> determination of reaction and phase transformation kinetics and mechanisms in condensed media. The theory is developed from the thermal diffusion equation for thin slabs of materials with a finite optical absorption coefficient undergoing a first-order process. The ratio of the photo-response to the total thermal response is evaluated for various reaction kinetics, and a series of time-resolved spectra is constructed.
J. R. Schoonover and S. H. Lin, "A Model for Time-Resolved Photothermal Spectroscopy of Reactions in Condensed Media," Appl. Spectrosc. 43, 1265-1269 (1989)