DEVITRIFICATION
Etymology
Noun
devitrification (countable and uncountable, plural devitrifications)
The formation of small crystals in a glass as a result of slow cooling from the molten state
Source: Wiktionary
De*vit`ri*fi*ca"tion, n.
Definition: The act or process of devitrifying, or the state of being
devitrified. Specifically, the conversion of molten glassy matter
into a stony mass by slow cooling, the result being the formation of
crystallites, microbites, etc., in the glassy base, which are then
called devitrification products.
Source: Webster’s Unabridged Dictionary 1913 Edition