Interconversion between non-bridging oxygen hole center and peroxy radical in F2-laser-irradiated SiO2 glass

Formation processes of the peroxy radical (POR) were examined in high-purity SiO2 glass exposed to F2-laser light which creates mobile atomic oxygen (O0) by photolyzing the interstitial oxygen molecules (O2). It was proved that under these conditions POR is formed by a reaction of the non-bridging oxygen hole center (NBOHC, an oxygen dangling bond) with O0, not by a reaction between the E′ center (a silicon dangling bond) and O2. Subsequent exposure to KrF laser light photolyzes POR and recoveres NBOHC by dissociating the O–O bond in POR. These findings corroborate the important role of O0 in defect processes in SiO2 glass.