Glucose or corn syrup is used to prevent the sugar from recrystallizing and becoming opaque, by disrupting the orderly arrangement of the molecules.
Cream of tartar is also used for this purpose, converting the sugar into glucose and fructose.
[2] Because sugar glass is hygroscopic, it must be used soon after preparation, or it will soften and lose its brittle quality.
[5] Sugar glass with blue dye was used to represent the methamphetamine in the AMC TV series Breaking Bad.
[6] Actor Aaron Paul would eat it on set.