Positron lifetime of ZnO-based scintillating glasses (55 - x) SiO2-45ZnO-xBaF(2) (x = 5, 10, 15 mol%) were measured with a conventional fast - fast spectrometer. Three positron lifetime components tau(1), tau(2), and tau(3) are similar to 0.23 ns, similar to 0.45 ns, and similar to 1.6 ns, respectively. All the three positron lifetime components first increase with increasing BaF2 concentration from 5 mol% to 10 mol%, then decreases as BaF2 further increases to 15 mol%. The result suggests that the glass sample with 10 mol% BaF2 contains the highest defect density, and is in excellent agreement with glass chemistry, glass density, thermal properties, and calculated crystallinity. Therefore, positron annihilation lifetime measurement is an effective tool for analyzing defects in ZnO-based scintillating glasses. (C) 2009 Elsevier B.V. All rights reserved.