Photoionization of As, Sb, Sn, and Pb in metaphosphate glasses

Solarization in glasses is of interest for photosensitive or photoresistant applications. Irradiation induced defects are studied in laser irradiated (248 nm) doped NaPO3 · 2Sr(PO3)2 glasses, and characterized by UV–VIS and EPR-spectroscopy. Solarization decreases from Pb, As, Sb to Sn. The life time of the defects is enhanced in doped compared to undoped glasses. Lead is photoreduced to (Pb2+)− and antimony is photooxidized to (Sb3+)+. EPR signals of an arsenic-related defect are observed and the formation of arsenic-hole centers is deduced from optical spectroscopy. Tin is both photoreduced and photooxidized. An EPR signal at g ∼ 1.989 is assigned to a “Sn3+” analogous defect.