POLARIZED RAMAN-SPECTRA OF ORIENTED POLYMER SYSTEMS - POLYACETYLENE AND COPOLYMER POLYACETYLENE-POLYNORBORNENE

In this paper, we present experimental and theoretical Resonance Raman studies carried out on oriented polymer systems. It is shown that different oriented trans polyacetylene samples exhibit Raman features which depend upon the stretching ratio. Also, the depolarization ratio of the Raman bands have been found to depend upon the isomerization temperature. Oriented copolymers polyacetylene/polynorbornene, (CH)x - (NBE)n - (CH)x, have also been studied. Raman spectra of the trans-(CH)x parts of these compounds have been analyzed in the frame of the bimodal distribution model. It is shown that whatever x and n values, results are rather similar in terms of conjugation length. In addition, from IR studies, one can deduce that in the stretched oriented copolymers, polynorbornene and polyacetylene segments have a different orientation degree.