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

The electron paramagnetic resonance (EPR) in experimentaloptical glasses obtained from the East Sayan mountain quartzites has beenstudied. For comparison a powder sample of cristobalite that formed duringthe beneficiation process of quartzite was also investigated by EPR. Thecomplex EPR spectra of fast-electron-irradiated glass andcristobalite were treated by computer simulations to determine the types of centers and their principal g values. In glasses the well-known paramagnetic centers , , have been observed. In particular, thecenter previously characterized as stableonly below was observed as a stable variantat room temperature. In cristobalite the paramagnetic defects similar to the , , centers with slightly different g values have been observed. From the observation of analogous centers it was inferred that local structuresof glass and -cristobalite aresimilar.