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Structural and chemical heterogeneity in ancient glass probed using gas overcondensation, X-ray tomography, and solid-state NMR

Rigby, Sean P.; Stevens, Lee; Meersmann, Thomas; Pavlovskaya, Galina E.; Rees, Gregory J.; Henderson, Julian; Bryant, Saffron J.; Edler, Karen J.; Fletcher, Robin S.


Professor of Chemical Engineering

Senior Research Fellow

Gregory J. Rees

Saffron J. Bryant

Karen J. Edler

Robin S. Fletcher


Rare ancient glasses have complex, multi-scale structures requiring more sophisticated and non-destructive pore characterisation techniques than usual. Homotattic patch models for nitrogen adsorption gave better fits to the isotherm data, more accurate void space descriptors, and also greater understanding of the underlying physical factors affecting adsorption, than standard BET. These homotattic patch models revealed the critical role of iron impurities in determining adsorption behaviour. Non-destructive sodium-23 NMR relaxometry validated the homotattic patch model for some natron glasses, and, in turn, was validated using multiple quantum magic-angle spinning (MQMAS) 23Na NMR. X-ray tomography images of the glasses showed the presence of large macroporous bubbles, while FEG-SEM revealed nanopores within the glass matrix. A newly-developed, gas overcondensation technique, suitable for small amounts of low porosity material, assessed the inter-relationship between the disparate levels in this hierarchical porosity. This technique demonstrated that the nanoporosity did not form a ‘corona’ around the bubbles, due to leaching from the glass, as initially supposed from tomography data, but was completely disconnected, and, thus, is probably associated with glass alkalinity. Gas overcondensation is demonstrated as a non-destructive alternative to mercury porosimetry for probing multi-scale porosity in rare artefacts.


Rigby, S. P., Stevens, L., Meersmann, T., Pavlovskaya, G. E., Rees, G. J., Henderson, J., …Fletcher, R. S. (2020). Structural and chemical heterogeneity in ancient glass probed using gas overcondensation, X-ray tomography, and solid-state NMR. Materials Characterization, 167, Article 110467.

Journal Article Type Article
Acceptance Date Jun 25, 2020
Online Publication Date Jun 27, 2020
Publication Date Sep 1, 2020
Deposit Date Jun 30, 2020
Publicly Available Date Jun 28, 2021
Journal Materials Characterization
Print ISSN 1044-5803
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 167
Article Number 110467
Keywords Mechanical Engineering; General Materials Science; Mechanics of Materials; Condensed Matter Physics
Public URL
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