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

Abstract

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.

Historic K-rich silicate glass surface alteration: Behaviour of high-silica content matrices

“…Moreover, the alteration of potassium-rich or potash-lime-silica glasses (often noted PLS or K-Ca-Si glasses) have extensively been applied to medieval stained-glass windows (e.g. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]), and less to medieval artifacts (e.g. [3]).…”

“…Usually, the impact of water, acids or bases on the deterioration of glasses represents a much greater amount of research data than the one on deterioration due to the interaction with the atmosphere [14,19,22,23], and even less specific to the museum environmental problems, which are sometimes dedicated to the very important identification of more susceptible glass objects [24][25][26][27]. Some cases have been reported of atmospheric exposures of K-Ca-Si glasses where the main forms of deterioration in aqueous solutions (leaching and congruent dissolution) were also observed [19].…”

In situ nuclear-glass corrosion under geological repository conditions

“…Glass corrosion that occurs when in contact with aqueous media has been studied in many fields, such as biogeochemical weathering of volcanic glasses in seawater, 1,2 CO 2 sequestration, 3 historical and archaeological artefact conservation, 4,5 and industrial applications. 6,7 The chemical durability of silicate glasses makes them suitable for high-level radioactive waste (HLW) containment that arises from dismantling operations or spentfuel recycling processes.…”

Glass alteration in atmospheric conditions: crossing perspectives from cultural heritage, glass industry, and nuclear waste management

“…When this mechanism prevails, it induces an increase of hydration rate and corresponding decrease of chemical durability. Its occurrence may not be systematic: for instance, in the case of medieval stained glass, careful experiments with D 2 18 O and nano-SIMS imaging put in evidence only the interdiffusion mechanism 83 . On the other hand, it may be severely dominating with dramatic consequences, as in the case of the mixed-alkali lime glass of CH aged at 80°C and 85% RH, where a thick hydrated, depolymerized layer with same composition as the pristine glass, except the additional water, was the only alteration phase to be observed 79 .…”