Effect of aluminum chloride on formation of a polyconjugated bond system in the initial stage of polyvinyl alcohol thermal decomposition

Abstract

Fine-structure bands have been located in electronic absorption spectra of polyvinyl alcohol (PVA) films decomposed thermally in air at 80–150°C. Doping of the PVA film with aluminum chloride (thermolysis catalyst) was found both to enhance the degree of thermal decomposition and to reduce the starting temperature for formation of poly-π-conjugated chains although it had no effect on the spectral positions of the polyene-unit absorption bands. Values of the band gap of heat-treated PVA films were determined to be in the range 1.65–1.78 eV based on an analysis of the electronic spectra long-wavelength edge.