IS METALLIC OR IONIC SODIUM RESPONSIBLE FOR GLASS BROWNING BY ELECTRON IRRADIATION?

摘要

Over the last decades there has been substantial dispute about the nature of sodium species in electron-irradiated glasses. In our laboratory, the nature of sodium has been studied in different glasses and under various irradiation conditions. This work leads to the conclusion that under the influence of low energetic electrons sodium diffuses to the surface where it becomes metallic. In the case of high energetic electrons, sodium diffuses to the maximum penetration depth of these electrons and remains in the ionic state. The species present after different irradiation conditions have been characterized by XPS, NAA, FT-IR and UV-Vis measurements. Notably FT-IR and XPS spectra as a function of depth show that ionic rather than metallic sodium species are present in the browning region after irradiation with high energetic electrons.