The pyroelectric response U(pi) of triglycine sulphate/polyethylene oxide composites is investigated by the photothermomodulation method in the course of polarization reversal under the action of an external voltage V. The thermowave profiles derived from the dependence of U(pi) on the IR-flux modulation frequency indicate changes of the distribution of pyroelectric parameters over the thickness at different polarization reversal stages. The study of U(pi) (V)-loops shows a large start-finish voltage interval of the polarization reversal. Two phases in the polarization reversal that are distinguished by a difference in time scales in the polarization switching process are revealed. The thermowave probing proved to be all efficient tool for studying the polarization reversal in ferroelectric particles in multiphase matrices,