Long-term weathering rate of stained-glass windows using H and O isotopes

Loryelle Sessegolo (1) , Aurélie Verney-Carron (1) , Mandana Saheb (1) , Laurent Remusat (2) , Adriana Gonzalez-Cano (2) , Nicolas Nuns (3) , Jean-Didier Mertz (4) , Claudine Loisel (4) , Anne Chabas (1)

1 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
2 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
3 IMEC - Institut Michel Eugène Chevreul - FR 2638
4 LRMH - Laboratoire de recherche des monuments historiques

The understanding of glass alteration is a biogeochemical, industrial, societal (radioactive waste confinement), and cultural heritage issue. Studies have been mainly performed in aqueous conditions. However, glass reactivity under hydraulically unsaturated conditions may be more important than previously recognized. In this context, we evaluate here the role of the alteration layer formed on medieval stained-glass windows on the ongoing alteration in unsaturated conditions. H 2 O adsorption isotherms were measured to study the relation between the vapor sorption and the relative humidity inside the alteration layer. From it, the average pore radius was calculated, yielding a water vapor diffusion coefficient of 7.8 × 10-7 m² s-1 inside the pore network. Experiments using doped water vapor (D 2 18 O) confirm the vapor transport up to the alteration front via fractures and pore network. They also demonstrate that the alteration mainly progresses via an interdiffusion mechanism. The calculated interdiffusion coefficients at 20 °C are 3.6 × 10-20 m 2 s-1 at 70% RH and 4.9 × 10-20 m 2 s-1 at 90% RH, which is similar to the values measured on model stained-glass samples altered in short durations (1-4 years). Therefore, this study highlights that, given its morphology, the alteration layer is not protective against vapor transport and interdiffusion.

Domaines: Chimie; Sciences de l'environnement

Loryelle Sessegolo, Aurélie Verney-Carron, Mandana Saheb, Laurent Remusat, Adriana Gonzalez-Cano, et al.. Long-term weathering rate of stained-glass windows using H and O isotopes. npj Materials Degradation, 2018, 2, ⟨10.1038/s41529-018-0038-1⟩. ⟨hal-03663303⟩