Decomposition of peroxy radicals in SiO₂ glass with X-rays or KrF laser light

Decomposition of the peroxy radical (POR) was examined for wet SiO ₂ glasses exposed to X-rays from a Rh-target tube or KrF laser light. The exposure to KrF laser light destroys POR resulting in the selective formation of the oxygen dangling bond (termed "non-bridging oxygen hole center", NBOHC). In contrast, the exposure to X-rays creates both the silicon dangling bond (E' center) and NBOHC on bleaching of POR. Clear mutual correlation is found between the formation kinetics of the interstitial oxygen molecule (O₂) and of the Si-Si bond but not between those of O ₂ and the E' center. These observations indicate that O₂ is created mainly from the radiolysis of the Si-O-Si bond by the Frenkel mechanism rather than by the dissociation of the Si-O bond in POR. It is concluded that both of KrF laser light and X-rays primarily dissociate the O-O bond in POR.