Optical Properties of Polyvinyl Alcohol doped with CoCl2

Abstract

Optical absorption measurements in the spectral range 4000–50000 cm^–1 were performed on cast thin films of polyvinyl alcohol(PVA) and its composites with cobalt chloride (CoCl₂). Identification of the structure and assignments of energy bands have been derived in terms of the ligand field theory. A mechanism based on the equilibrium between six-coordinated and four-coordinated symmetry is proposed to account for the obtained spectra. Such equilibrium is attributed to a small difference between the stabilization energies, and the symmetry is found to be altered with cobalt chloride concentrations.