glassify vs vitrify

glassify

verb
  • Synonym of vitrify: to convert a silica-bearing material to a glasslike substance by applying heat. 

  • To convert (radioactive waste) into a glasslike substance for long-term storage. 

  • To the convert sand or soil of (a particular geographic area) to a glasslike state using the heat from a thermonuclear detonation. 

vitrify

verb
  • To convert into glass or a glass-like substance by heat and fusion. 

  • To be converted into glass, especially through heat. 

How often have the words glassify and vitrify occurred in a corpus of books? (source: Google Ngram Viewer )