Photoinduced absorption of soluble trans polyacetylene with low content of defects

Summary form only given. Photoinduced absorption measurements of soluble trans-polyacetylene (s-PA) with low content of defects were carried out in visible and near infrared region. The steady state photomodulation spectrum of a-PA shows in-phase high energy (HE) band at 1,53 eV similar to that observed for Shirakawa or Durham-routs samples, bleaching bands at 1,65 and 1,77 eV with phase delay about /spl Pi//8 related to a pump signal, and the absence of low energy (LE) band at 0,5-0,8 eV. The results obtained for s-PA differ from those known for other PA types: (1) The 1,5 eV band of s-PA is observed up to room temperature. (2) The LE band is not observed. (3) The 1,65 and 1,77 eV bands were not observed earlier for other PA samples. The bands 1,65 and 1,77 eV are thermochromic in their nature and are associated with laser heating of s-PA particles by the pump beam. We have supposed that all these results are connected with low content of defects in s-PA.