You searched for: “devitrifying
devitrify (verb), devitrifies; devitrified; devitrifying
1. To change from a glassy to a crystalline state and become brittle and opaque, or to cause a material to do this.
2. To cause (a glassy material) to become crystalline and brittle.
3. With reference to a volcanic rock or to a particle; to undergo a change in texture from glassy to crystalline.