Raman and infrared studies on the molecular structures of poly(1,4-phenylenevinylene) and poly(2,5-thienylenevinylene)

The Raman and infrared spectra of poly(1,4-phenylenevinylene) (PPV) and poly(2,5-thienylenevinylene) (PTV) show that extensive π-electron conjugation take place in both polymers. There are indications that the phenylene ring in PPV is considerably different from a typical p-phenylene ring. The peak wavenumbers and bandwidths of a few Raman bands of PTV depend on the excitation wavelength. This observation is explained as a result of existence of segments with various lengths of π-electron conjugation. No bands in the Raman spectrum of PPV show such behavior.