Fused silica platelets were implanted or co-implanted with Na, Mg and Al and were annealed in 1atm of flowing O at 900C. The concentration depth profiles of these elements were monitored by means of secondary ion mass spectrometry, before and after annealing. It was found that the presence of Na markedly accelerated the diffusion of Mg. The incorporation of Al significantly retarded the diffusion of Na and Mg.

Sodium-Accelerated Diffusion of Magnesium in Silica and Its Retardation by Aluminum. P.Mukundhan, H.H.Du, S.P.Withrow: Journal of the American Ceramic Society, 2002, 85[6], 1613-5