Sentence:  Her work was endless, she carried tubs and cauldrons and pails of heat-blasted sand, sand blasted into liquid glass, up the ladder that had <WSD>vitrified</WSD> where her bucket splashed, and tipped the liquid glass into the swimming pool, where, at the touch of the water, it turned into her huge, solid tears. 
Meaning of the word marked with <WSD> tags:  To be converted into glass, especially through heat.