Glasses with the composition (SiO2)(50)(GeO2)(50-x)(Na2O)(x) (x=0, 20-40) were synthesized at 1600 degrees C by melting in air, and their photoluminescence properties were investigated. Furthermore, the formation of non-bridging oxygens (NBOs) and oxygen vacancies in the (SiO2)(50)(GeO2)(50-x)(Na2O)(x) glasses was examined using X-ray photoelectron spectroscopy. In contrast to the violet-blue emission of the (SiO2)(50)(GeO2)(50) glass, the (SiO2)(50)(GeO2)(20)(Na2O)(30) glass exhibits a quasi-white emission under ultraviolet light. The internal quantum efficiency of the (SiO2)(50)(GeO2)(20)(Na2O)(30) glass at an excitation wavelength of 250 nm was 37%. It was confirmed that the number of NBOs increases with the addition of Na2O in (SiO2)so(GeO2)so glass. (C) 2017 Elsevier GmbH. All rights reserved.