UNDERSTANDING AND PREDICTING GLASS DETERIORATION IN MUSEUM COLLECTIONS
The deterioration of glass concerns museums worldwide. Approximately 10% of historical, post-medieval glass is chemically unstable, resulting in the development of unwanted changes in appearance. These changes range from the development of moist layers, to the formation of a network of hairline cracks on the glass surface. These patterns are the result of irreversible chemical changes and may render an object completely unfit for display. Preventing the occurrence of these degradation patterns is therefore of great importance to conservators and curators.
Therefore, an early warning system for the identification of vulnerable glass objects was developed during a PhD-project. This was based on the notion that certain elements, notably sodium and potassium, leach out of the glass structure and react on the glass surface with atmospheric molecules to form salts. It was shown that the presence of these ions in low concentration can be an indication of the unstable nature of the glass.
In the current project, the research focuses on understanding why and how these ions migrate to the surface and how their presence on the surface can be related to the chemical changes in composition. The aim is to further the understanding of glass deterioration in museum collections and to improve existing guidelines for the safe storage of unstable glass.
- Verhaar, G; M van Bommel; N Tennent 2020, ‘Development and validation of an analytical protocol for the sampling and quantitative analysis of ions on the surface of unstable historic glass in museum collections using ion-exchange chromatography’, Journal of Chromatography A, Volume 1627, Article 461394.
- Verhaar, G., N.H. Tennent, J.T. Van Elteren, V.S. Šelih, en M. Šala. 2019. ‘Investigating Ion Depletion in Unstable Historic Glass Samples Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry and Ion Chromatography’. In Recent Advances in Glass and Ceramics Conservation 2019, onder redactie van J. Mandrus en V. Schussler, 45–54. London: ICOM Committee for Conservation.
- Verhaar, G., M.R. Van Bommel, en N.H. Tennent. 2019. ‘The implementation of ion chromatography as a key analytical technique for investigation of unstable glass in museum collections’. In Glass Atmospheric Alteration. Cultural Heritage, Industrial and Nuclear Glasses, onder redactie van I. Biron, F. Alloteau, P. Lehuédé, O. Majérus, en D. Caurant, 162–68. Paris: Hermann.
- Verhaar, G 2018, Glass sickness: Detection and prevention – Investigating unstable glass in museum collections. PhD-thesis, University of Amsterdam.