Diffusion experiments, with sol–gel derived isotopically enriched silica glasses, were performed at between 1050 and 1300C. The diffusion profiles were measured by means of time-of-flight secondary ion mass spectrometry. Samples annealed in closed silica ampoules, under Ar or dry air, exhibited enhanced Si diffusion as compared with Si diffusion in fused silica. Annealing in a large alumina tube, under an 18O2 ambient, yielded Si and O diffusion coefficients which approached the results for thermally grown SiO2. Enhanced Si diffusion in sol–gel derived glass was suggested to be due to water residues which led to the formation of silanol SiOH groups.

Silicon Diffusion in Sol–Gel Derived Isotopically Enriched Silica Glasses. H.Bracht, R.Staskunaite, E.E.Haller, P.Fielitz, G.Borchardt, D.Grambole: Journal of Applied Physics, 2005, 97[4], 046107 (3pp)