Analysis of films and gels based on polyvinyl alcohol having thermochoromic properties with methods of UV and impedance spectroscopy

Thermochromic materials have gained importance, due to their extensive use in a number applications including; room thermometers, refrigerators, aquariums, textile industry, physiology and medicine, jewelry, microwave systems, production of dyes and pigments, and fabrication of fiber optical sensors. In this study, dielectric properties of doped polyvinyl alcohol films and thermochromic properties of jells have been investigated. In polyvinyl alcohol, cobalt (II) chloride and orthophosphoric acid were used as dopants. The dielectric properties of various films, which were generated by independently varying the molecular weight of polyvinyl alcohol, concentration of cobalt (II) chloride, and orthophosphoric acid, were measured by impedance spectrometry and compared. The variation of absorbance, as a result of temperature induced pH changes, in polyvinyl alcohol based basic and neutral jells, were measured by a Lambda 900 model UV-VIS-NIR spectrophotometer, and the thermochoromic properties were determined. Key Words : Thermochromic, dielectric