The irradiation-sensitive defect structures of pure anhydrous and hydrated fused amorphous samples were investigated by using cathodoluminescence micro-analysis. Irradiation with a continuous stationary electron beam resulted in a sub-surface trapped-charge induced electric field which caused the electromigration of mobile charged defect species within the volume of the irradiated specimen. Cathodoluminescence emissions, observed between 300 and 900nm at temperatures ranging from 5 to 295K, were correlated with particular defect centers; including the non-bridging O-hole centers with strained bond and/or non-bridging hydroxyl precursors (in hydrated specimens), the self-trapped exciton, O-deficient centers (such as the neutral O vacancy and/or the 2-fold coordinated Si defect) and the charge-compensated substitutional Al center.

M.A.S.Kalceff: Physical Review B, 1998, 57[10], 5674-83