Crizzling of Historical Glasses

Nefeli Avgerou and Marcin Strojecki presented their new results on crizzling of historical glasses at the II Konferencja Naukowo-Techniczna “Epoka Szkła” (2nd Scientific and Technical Conference "The Glass Age").Historical glasses are common artefacts in museum environments, and they often undergo hydration due to their chemical instability, forming a so-called hydrated layer on their surface. Subsequent relative humidity drops, can cause this layer to crack. The process of development of a network of microcracks on the hydrated layers' surface is called crizzling. The relative humidity ranges proposed in literature for storing such glasses, are general and based on conservators' observations. The RH range for crizzled glasses proposed by Koob is very stringent (40-42% RH), making it difficult to maintain from a technical point of view but also increasing the consumption of energy in museum environments. The literature predominantly is focused on studying the mechanisms of hydration of historical glasses, whereas our aim is to characterize mechanically the hydrated layer, with the use of the Acoustic Emission technique, in order to better understand the process of crizzling aspiring to update the museum specifications in the future.