fibreglass vs vitrify

fibreglass

verb
  • To apply fibreglass to. 

noun
  • Silica based glass extruded into fibers that possess a length at least 1000 times greater than their width. 

  • A composite material made from fine fibres of spun glass held together with resin. 

vitrify

verb
  • To be converted into glass, especially through heat. 

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

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