Photoinduced Infrared bands in short polyacetylene segments

We present the theoretical analysis of the photoinduced absorption infrared spectra of Durham type polyacetylene and diblock copolymers. Good agreement with experimental data is found, taking into account the contribution of short segments, in all these samples, expecially in the case of Durham type (CH)x exposed to air. In particular we have well reproduced the different structures of the low frequency absorption band in the photoinduced spectra.