For spectral holography, the opportunity of using real-time information recording in situ using photothermoplastic (PTP) materials is considered, Applying the physical model of free charge carrier photogeneration for photothermoplastics (PTPs), based on charge transfer complexes, the photosensitivity is investigated considering its dependence on exposure time (exciting laser pulses duration), For sequential PTP processes, it is shown that the experimental Values of the photosensitivity over a spectral range of 300-1000 nm is maintained down to picosecond exposures. This is in good agreement with theoretical calculations. It is concluded that, for the achieved values of photosensitivity and taking into account other characteristics of PTPs-such as real-time recording in situ, high values of space resolution (to 1000 line pairs mm(-1)), diffraction efficiency (to 20%) and cyclability (to 1000 cycles)-PTPs are useful materials for laboratory investigations in the field of spectral holography. Copyright (C) 1996 published by Elsevier Science Ltd.