Multianalytical characterization of Late Roman glasses including nanosecond and femtosecond laser induced breakdown spectroscopy

In the present study, a historical set of Late Roman glasses from a recently unearthed graveyard located in the small city of Cubas de la Sagra, within the Madrid region (Spain) was compositionally analysed using different techniques such as ultraviolet-visible (UV-Vis) and laser induced fluorescence (LIF) spectroscopy, X-ray fluorescence (XRF) and laser induced breakdown spectroscopy (LIBS). LIBS results, recorded upon nanosecond (ns) and femtosecond (fs) laser irradiation, served for identification of major glass components (to classify them into main historical glass groups) and of minor components (e.g. chromophores, decolouring agents and degradation products). Quantitative information regarding these components was obtained on the basis of calibration curves obtained using glass certified standards and local standards. We have demonstrated that LIBS serves for the non-invasive/micro-destructive, quantitative chemical characterization of most of the analysed historical glasses. Furthermore, this work establishes a comparison between LIBS analysis of glasses in the ns and fs regimes on one hand, and on the other hand with the results obtained using XRF. The procedures and protocols here proposed can be applied for in situ study of historical glass collections, regardless of their size, provenance and chronology.This work was funded by MINECO (Project CTQ2013-43086-P, HAR2012-30769 and FIS2013- 44174-P) and Programa Geomateriales 2-CM (CAM, S2013/MIT-2914) and counted with the support from Techno-Heritage (Spanish Network of Science and Technology for Heritage Conservation). M. Oujja acknowledges CSIC for a contract