We synthesized and investigated the luminescent properties of undoped and Pb- or Sn-doped CaO-Al2O3-SiO2-GeO2 (CASG) glasses. Blue light emission from the undoped CASG glass with a high emission yield (75.4%) was presented. The intensity of the blue emission had a good linear relationship to the detectable electron spin resonance signal, which confirmed that the blue emission originated from Ge-related oxygen-deficient centers (GODCs) in these glasses. Furthermore, we also demonstrated tunable luminescence with an emission yield from blue (57.2%) -> white (39.6%) -> yellow (56.1%) in the Pb-doped CASG glass. White light with an emission yield 64.1% in Sn-doped CASG glass was also presented. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3253617] All rights reserved.