RESONANCE RAMAN-SPECTROSCOPY OF POLYENE COMPOUNDS (MULTIMODE SYSTEMS)- POLYACETYLENE SYNTHESIZED FROM CYCLOOCTATETRAENE

Specific features of the excitation spectra of resonance Raman (RR) li nes in multimode systems were characterized. Based on this, the spectr a, the structure, and the composition of polyacetylene (PA) synthesize d by polymerization of cycloocta-1,3,5,7-tetraene in the presence of m etathesis catalysts were investigated. A dependence of frequencies and intensities of the C-C and C=C stretching lines on the exciting light wavelength was found and explained by broad distribution of defect-fr ee conjugated polymer segments in the PA samples studied on the number of double bonds incorporated in them. A procedure for the calculation of the distribution functions and of the shapes of RR lines was propo sed. These functions are bimodal. A reversible cis-trans-transition wa s discovered in the PA samples not subjected to heat treatment, which was attributed to the presence of macrocyclic polyene structures.