Structural characterization of the glassy phase in majolica glazes by Raman spectroscopy: A comparison between Renaissance samples and replica processed at different temperatures

Tin-opacified lead glaze, prepared according to Renaissance recipes, has been fired at different temperature from 300 °C to 990 °C, and investigated by Raman scattering. A chemometric treatment and a systematic curve-fitting procedure have been applied in the range of 700–1250 cm⁻¹ in order to monitor quantitatively the structural changes of the silicate network that occurred with firing. The results obtained on model glazes are compared with Raman spectra collected on various Renaissance potteries. This method is suggested for non-invasive surface analysis of ancient glazes aimed at the characterization of processing techniques.