The role of mobile interstitial oxygen atoms (O(0)) in defect processes in oxides is demonstrated by interconversion between the oxygen dangling bond and the peroxy radical (POR) in SiO2 glass. Superstoichiometric O(0) was created by F2 laser photolysis of the interstitial O2. On annealing above 300 degrees C, O(0) migrated and converted the oxygen dangling bond to POR. Exposure to 5.0 eV light converted POR back to a pair of the oxygen dangling bond and O(0) (quantum yield: approximately 0.1). These findings suggest that various defect processes typically occurring in SiO2 glass at approximately 300-500 degrees C are related to migration of O(0), which exists in the glass network in the peroxy linkage form.
