Structure of latent tracks created by swift heavy ions in amorphous SiO2 and zinc phosphate glass

The structure of latent tracks introduced by swift-heavy-ion irradiation was examined on both amorphous SiO2 and zinc phosphate glass (68P(2)O(5):25ZnO:4.5Al(2)O(3):2.5Na(2)O). In amorphous SiO2, the frequency of the infrared absorption assigned to the asymmetric stretching vibration of Si-O decreased with irradiation. This IR peak shift has been found to be related to the transition of normal six-membered rings of SiO4 tetrahedra to planar three-membered rings. The high etching rate of the latent tracks is strongly related to planar three-membered rings. In the ion-irradiated zinc phosphate glass, two bridging oxygen atoms bound to a phosphorus atom turned into one bridging oxygen atom. Scission of the Zn-O bond was not observed. It was concluded that the high etching rate of the latent tracks in zinc-phosphate glass is related to P-O bond scission.