Effects of aluminum impurity on the structural relaxation in silica glass

Structural relaxation of SiO2 at elevated temperatures monitored by in situ Raman scattering

“…Fig. 10 shows that the activation energies for the present low-OH synthetic silica glass and the very low-OH GE214 almost coincide, in agreement with the very low concentration of relaxation-enhancing impurities in both glasses (the Al content of GE214 inhibits relaxation [24]). The 1200 ppm-OH Suprasil 1 shows, as expected, shorter relaxation times than the 880 ppm OH sample of this work, but it also exhibits a significantly smaller activation energy.…”

Viscosity of silica glass prepared from sol–gel powder

“…On the other hand, the synthetic silica glass has a lower viscosity than that of fused natural quartz glass. This is because the fused quartz glass generally contains Al in the concentration of about 10 wt ppm or more depending on the sources of natural quartz powders, which increases viscosity [7,8] and structural relaxation time [9] of silica glass. To improve the viscosity of the high purity synthetic silica glass, doping of the silica glass with a trace amount of Al is the most probable way.…”

Microscopic Features of Biologically Formed Amorphous Silica

“…A similar approach on Cauxi could lead to the production of mesoporous amorphous silica without the incorporation of water into the glass structure since water incorporation weakens the strength and thermal properties of the silica glass. The technological and scientific importance of glassy silica is demonstrated by its wide applications such as membranes (de Vos & Verweij, 1998), columns (Dai et al, 2003), heatproof materials (Saito et al, 2000), optical communication fibres (Tong et al, 2003) and catalysts in organic synthesis (Minakata et al, 2004). At present, silica of high purity is often produced by means of fusing (Brückner, 1970;Tohmon et al, 1989) or argon plasma methods (Tohmon et al, 1989).…”