Is glass brittle at all scales?

Although silicate glass is considered as the archetype of brittle materials, which break without deforming irreversibly, its fracture involves some dissipation. By examining the post-mortem fracture surfaces, by following in situ the progression of a stress corrosion crack and by measuring the depth of penetration of water in the material during slow fracture, we show that glass behaves in fact in a quasi-brittle manner, with a damaged zone of ∼10 nm developing ahead of the crack tip.