TOF-SIMS analysis of corroding museum glass

Corrosion salts form on the surface of vulnerable low lime glass as it corrodes and if left to develop, reduce the clarity of the object and ultimately permanently damage and stain the glass surface. The glass artefacts must therefore be cleaned to remove these corrosion products as they appear. The cleaning procedure used must not, of course, speed up the deterioration process. However, the effect of cleaning procedures on glass objects has not been monitored systematically to date. In this work, a replica museum glass was cleaned using a known surfactant (Synperonic N) and then aged at 40%RH and room temperature for 1 week. A sample which had not been cleaned was also aged under the same conditions. The glass was then analysed and imaged using an ION-TOF GmbH SIMS instrument (TOF.SIMS 5) fitted with a Bismuth ion source. The results showed that the corrosion salts were forming heterogeneously across the surface of the glass and analysis of these salts indicated the presence of formates and carbonates.