The Raman signature of protonic species as a potential tool for dating or authentication of glazed pottery
Résumé
In this study, the potential of Raman spectroscopy is discussed for the comparative dating/authentication of glazed ceramics on the basis of the Raman signature of protonic species incorporated in the glazes due to the corrosion processes as a function of time, chemical composition and environmental conditions. According to the literature and analyses on a reference set of glass samples which had been previously subjected to heavy corrosion in laboratory conditions and extensively studied by Infrared spectroscopy, the accumulation of protonic species such as water and hydroxyl groups on the surface of the silicates gives rise to a specific Raman signature in the 2000-3700 cm-1 range. The intensity of the related bands of this Raman signature is mainly considered to act as a means of discriminating between old and modern artefacts. In order to check this hypothesis, glazed ceramics with different origins (Chinese and Vietnamese stoneware/celadons, blue-and-white and painted enamelled porcelains; Islamic pottery) and different chemical compositions/processing conditions from a wide time span (~1000 to present) were analysed by Raman microspectroscopy. Further comparative data was obtained by modifying the experimental parameters such as the laser wavelength, objective magnification and confocal hole. The results showed that the Raman intensity of the protonic species shows a correlation with age for lead free glazed pottery in the case of celadons and porcelains. The intensity strongly depends on the chemical composition of the glaze as well as the conservation conditions to a certain degree.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
---|
Loading...