In-situ Raman Spectroscopic Characterisation of Polymers Used in past Conservation Treatments

This paper reports the successful characterisation of polymers from past conservation treatments using Raman spectroscopy with a fibre-optic probe. It has been demonstrated for the first time that this methodology is well suited to the in-situ examination of polymers used as adhesives and gapfillers for conservation of glass artefacts. By means of a Raman spectroscopic instrument with a fibre-optic probe, conservation polymer spectra were recorded non-destructively, with a spectral resolution of 2 cm-1 in the range 2003200 cm-1. Polymer identification proved straightforward for gap-fillers and, for adhesives, different polymers were also successfully distinguished, even in a glass / adhesive / glass bond less than 100 μm in width. In addition to polymer identification, Fe2O3 was identified as the pigment not only in restored areas but also in the original grisaille paint for the grey toning for the glass pictorial scene.