Ir and Raman studies in three polyanilines with different oxidation level

FT-IR and FT-Raman (1.17 eV excitation) spectra have been measured in three kinds of polyanilines; fully oxidized pernigeraniline base (PB), half oxidized emeraldine base (EB), and fully reduced leuceomeraldine base (LB). The degree of oxidation of each polymer was estimated by the intensity of some characteristics peaks, such as NH stretching, ring stretching, and CN modes. Raman spectra were also measured by Ar+ laser (2.41 eV) excitation. We found that the resonance Raman spectra in PB and EB are very similar to the non-resonance Raman spectrum in LB. This fact indicates that photoexcitation at 2.41 eV produces polarons (or bipolarons) subsequent to a structural conversion from quinoid to benzenoid form in PB and EB.