Source : Webster's Revised Unabridged Dictionary (1913)

Vitrify \Vit"ri*fy\, v. t. [imp. & p. p. {Vitrified}; p. pr. &
   vb. n. {Vitrifying}.] [F. vitrifier; L. vitrum glass +
   -ficare to make. See {Vitreous}, {-fy}.]
   To convert into, or cause to resemble, glass or a glassy
   substance, by heat and fusion.

Vitrify \Vit"ri*fy\, v. t.
   To become glass; to be converted into glass.

         Chymists make vessels of animal substances, calcined,
         which will not vitrify in the fire.      --Arbuthnot.

Source : WordNet®

vitrify
     v 1: change into glass or a glass-like substance by applying heat
     2: undergo vitrification; become glassy or glass-like
     [also: {vitrified}]