Intermediate-Range Order of Alkali Disilicate Glasses and Its Relation to the Devitrification Mechanism

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• 作者：James G. Longstaffe ; Ulrike Werner-Zwanziger ; Jose F. Schneider ; Marcio L. F. Nascimento ; Edgar D. Zanotto ; Josef W. Zwanziger
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：April 17, 2008
• 年：2008
• 卷：112
• 期：15
• 页码：6151 - 6159
• 全文大小：230K
• 年卷期：v.112,no.15(April 17, 2008)
• ISSN：1932-7455

文摘

There are two general mechanisms of devitrification in glass: heterogeneous nucleation of crystals fromsurfaces and impurities and homogeneous nucleation from the volume. It is thought that structural similaritiesbetween glass and crystal at the intermediate-range level influence the mechanism followed; however, thereare scarce experimental studies to test this hypothesis. In this paper solid-state nuclear magnetic resonancespectroscopy is used to probe intermediate-range order in sodium and lithium disilicate glasses throughmeasurement of the second moment of the distribution of dipolar couplings. These two glasses undergoheterogeneous and homogeneous nucleation, respectively. The second moments measured for the lithiumglass closely follow the trend established by the layered structures of the isochemical crystalline phases,while the same measurements for the sodium glass do not. This observation supports the hypothesis thatglasses capable of homogeneous nucleation are structurally more similar to the resulting crystalline phasesthan those glasses that exhibit only heterogeneous nucleation.