Webster’s Revised Unabridged Dictionary · 1913
Devitrification
De·vit′ri·fi·ca′tion (dē·vĭt′rĭ·fĭ·kā′shŭn), n. 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.