Identification of parameters involved in the photochemically induced degradation of CD-R phthalocyanine dye

This article focuses on the long term ageing of CD-R with phthlalocyanine dye. The aim of this preliminary research is to understand the chemical evolution of the dye and to find relevant parameters that could be correlated to the degradation of CD-R. This study reports on the chemical evolution of the phthalocyanine dye under light irradiation, either in solution in ethanol and cyclohexane, or in the solid state. A peculiar attention was given to the role played by oxygen in the degradation of the dye in solution. Analysis in solution was carried out by UV-visible spectroscopy, both in steady state and time resolved conditions. The study at the solid state was performed by in situ analysis of the dye with SEM and AFM on the polycarbonate layer obtained from commercial CD-R. In both cases, dye samples obtained from virgin and recorded CD-R were investigated. The results permit evidencing parameters representative of the degradation of the CD-R, such as the formation of photoproducts coming from the degradation of the dye which can be detected by UV-visible spectroscopy, or the modification of the topographic parameters at the surface, which can be analysed by AFM.