Structural study of Mg-bearing sodosilicate glasses by Raman spectroscopy

✍ Scribed by Nicolas Trcera; Stéphanie Rossano; Martine Tarrida

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 368 KB
• Volume: 42
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.2763

✦ Synopsis

Abstract

The presence of magnesium in glasses of geological, medical, and technological interests influences their physicochemical and durability properties. However, the understanding of the role of magnesium is dependent on the combined knowledge of the structural environment of magnesium in the glass or melt and of the silicate network connectivity of the studied systems. In this article, we present a Raman spectroscopic study of the network connectivity of 10 ternary silicate glasses in the system Na~2~OMgOSiO~2~ and one Mg‐free binary silicate glass Na~2~OSiO~2~. Results obtained at constant polymerization suggest the existence of various Q^n^ units according to the nature of the modifying cation. As polymerization decreases for Na~2~OMgOαSiO~2~ glasses (labeled as NMSα with α decreasing from 10 to 2), the band associated with SiOSi bending in fully polymerized region disappears being gradually replaced by a band attributed to SiOSi bending in region containing mainly Q^2^ and Q^3^ species. For highly polymerized glasses (NMS10‐NMS4), the coexistence of these two bands suggests the presence of two interconnected networks. Concomitantly, the signal associated with Q^3^ species first increases. For a further decrease of the polymerization, the high wavenumber part of the signal associated with Q^3^ species decreases, while the intensity of the high wavenumber part of the band related to Q^2^ species increases. This result strongly suggests that magnesium charge‐balances preferentially Q^2^ species rather than Q^3^ species. Copyright © 2010 John Wiley & Sons, Ltd.