Judit Molera participate in the ALBA Synchrotron Project to analyze the crystalline phases developed in stained-glass windows exposed to marine aerosols. Silicate glasses can be altered in marine atmospheres; however, their alteration mechanism is still uncertain. In this study, NaCl aerosols were deposited on different glasses and, afterward, were exposed to high humidity. The ion Na+ from the aerosols can be interchanged by the ions from the surface, forcing the opening of the glass lattice due to the steric distribution. This facilitates the lixiviation of alkaline elements from the glass that were dissolved in the adsorbed water. In case of high humidity, environmental gases (CO2, SO2…) can also be dissolved in the surface water and can react with the lixiviated elements to form carbonates or sulfates.

The main goal of this project is to analyze the crystals observed on the surface result of the interaction with the marine aerosols. Different difficulties have been presented for the analyses with other techniques. Normally, the deposits are microcrystalline and are spread on the surface, so common XRD equipment has not enough resolution to analyze them, additionally, they are on non-flat glasses, producing a high background masking the small signals from the crystals. For this study, a new procedure based on the peeling of the glass surface with Kapton and the subsequent analysis of the deposits adhered to it was proposed.

Dr. Teresa Palomar of Instituto de Cerámica y Vidrio is the IP of this project.