The effect of cooling rate on the structure of sodium silicate glass

The effect of cooling rate on the structure of Na2Si3O7 glass was studied by Raman spectroscopy. The shape of Raman spectra of glasses varies with cooling rate. By fitting the high-frequency region of the Raman spectra with Gaussian curves, the abundance of SiO4 tetrahedra with different number of non-bridging oxygens (Q(n)) are deduced. The structural species Q(4) and Q(2) increase with cooling rate and Q(3) decrease with cooling rate. Providing the faster cooling rate leads higher temperature feature of melt to preserve in glass, the changes of structural species in Na2Si3O7 glass with cooling rate are consistent with the in situ high-temperature Raman results. From this study the rate-dependent glass structure should be taken into consideration in the glass processing, even with ordinary cooling technique. (C) 2003 Elsevier B.V. All rights reserved.