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380 nm Photoluminescence Caused by Trace Na Impurity in High-Purity Synthetic Silica Glass

In this study, 380 nm photoluminescence (PL), in the high-purity synthetic silica glass containing trace Na impurity, is observed upon excitation with ultraviolet (UV) light of wavelengths less than 240 nm. Its intensity increases with Na concentration exceeding the 1:1 concentration ratio of Na to Al. The nonbridging oxygen, pairing with the excess Na, is assumed to cause the PL, as well as an increase in the intensity of the 185 nm absorption band.