Irradiation-induced defects in ionic sulfophosphate glasses

X-ray-induced defects in undoped and Ag-doped sulfophosphate glasses were studied by optical and electron paramagnetic resonance (EPR) spectroscopy. Besides intrinsic phosphate-related positively charged hole centers (HC) and negatively charged electron centers (EC), also oxygen hole centers (OHC), sulfate-related electron centers (SEC) and zinc centers (Zn*-HC) were identified. The formation of three different Ag-related defects was evident in the Ag+-doped glasses: (Ag+)− and (Ag+)2−-EC, as well as (Ag+)+-HC. Undoped glasses recover at room temperature within two weeks. In contrast, other defects are stabilized when Ag+ is present in the glasses, as some intrinsic defects transform over time at room temperature into more stable Ag-related defects.