Oxygen-diffusion kinetics in densified, amorphousSiO2

The dynamics of intrinsic defect creation and annealing have been studied in dry, amorphous ${\mathrm{SiO}}_2$ subjected to a hydrostatic pressure of 5 GPa at 600?deC. The compaction produced does not in itself result in the creation of significant numbers of paramagnetic defects but it does greatly enhance their creation efficiency when samples are subjected to subsequent γ irradiation. Annealing after irradiation results in a growth in the number of peroxy-radical defects and a correlated decrease in the number of oxygen-vacancy defects. The higher temperatures needed for annealing with respect to the case of undensified, amorphous ${\mathrm{SiO}}_2$ lead us to conclude that interstitial molecular-oxygen diffusion is severely inhibited in the compacted samples.