EPR study of the E′ defects in optical glasses and cristobalite

The electron paramagnetic resonance (EPR) in experimental optical glasses obtained from the East Sayan mountain quartzites has been studied. For comparison a powder sample of cristobalite that formed during the beneficiation process of quartzite was also investigated by EPR. The complex EPR spectra of fast-electron-irradiated glass and cristobalite were treated by computer simulations to determine the types of E' centers and their principal g values. In glasses the well-known paramagnetic centers E-gamma', E-alpha', E-delta' have been observed. In particular, the center E-alpha 1' previously characterized as stable only below T similar to 200K was observed as a stable variant at room temperature. In cristobalite the paramagnetic defects similar to the E-gamma', E-alpha 1', E-delta' centers with slightly different g values have been observed. From the observation of analogous E' centers it was inferred that local structures of glass and beta-cristobalite are similar. Copyright (C) 2021 EPLA