A high-energy X-ray diffraction, P-31 and B-11 solid-state NMR study of the structure of aged sodium borophosphate glasses

Qiu, Dong and Guerry, Paul and Ahmed, Ifty and Pickup, David M. and Carta, Daniela and Knowles, Jonathan C. and Smith, Mark E. and Newport, Robert J. (2008) A high-energy X-ray diffraction, P-31 and B-11 solid-state NMR study of the structure of aged sodium borophosphate glasses. Materials Chemistry and Physics, 111 (2-3). pp. 455-462. ISSN 0254-0584. (Access to this publication is restricted)

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Abstract

The structure of aged melt-quenched sodium borophosphate glasses of composition (P2O5)(40)(B2O3)(x)(Na2O)(60-x) (with x in the range 10-40) has been studied by high-energy X-ray diffraction (HEXRD), P-31 and B-11 magic angle spinning (MAS) NMR. Similar to the fresh samples, both P-O-P and P-O-B linkages are found to be present in these glasses. All three techniques show that the cross-linking between borate and phosphate units increases with boron oxide content. Distinctively upon aging, the glass is found to hydrolyze causing the network to degrade. At the same time, crystalline phases are now also observed. XRD and DTA show that the samples have a higher tendency towards crystallization with increasing boron oxide content upon exposed to moisture. P-31 and B-11 MAS NMR results are in agreement with these findings. TGA data show that samples with higher boron oxide content take up more moisture upon aging, suggesting that crystallization may be associated with glass hydrolysis. HEXRD results also suggest that sodium ions are preferentially associated with borate units with increasing boron oxide content. (C) 2008 Elsevier B.V. All rights reserved.

Item Type: Article
Additional information: Funding Acknowledgement: Funding Agency EPSRC Grant Number EP/C004671 EP/C004698 EP/C515560 Funding Agency University of Warwick
Uncontrolled keywords: sodium borophosphate glass high-energy X-ray diffraction solid-state NMR
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: J.M. Smith
Date Deposited: 13 May 2009 11:00
Last Modified: 03 Jun 2014 15:09
Resource URI: http://kar.kent.ac.uk/id/eprint/15963 (The current URI for this page, for reference purposes)
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