TEMPERATURE-DEPENDENT RESONANCE RAMAN-STUDY OF IODINE-DOPED POLY(VINYL ALCOHOL) FILMS

The resonance Raman spectrum of iodine-doped poly(vinyl alcohol) films was studied as a function temperature from 77 to 290 K. The main band s in the spectrum are assigned to fundamental and overtone bands of li near I-3(-) and I-5(-). The presence of combination bands in the spect rum is attributed to exciton coupling between these species in polyiod ide chains. The low-temperature measurements allowed us to resolve new spectral features. At 77 K, the spectrum showed evidence for minor am ounts of I-2 and isomers of the main polyiodide components. The optica l properties of the PVA-iodine complex are not simple and cannot be as signed to any single polyiodide species.