Our heat tempered glass is processed in accordance with ASTM C1048. Heat tempering increases the strength and thermal shock resistance of soda lime glass. Note that some optical distortion will be apparent. Fully tempered glass is also called safety glass because it will dice into small particles when broken. Heat strengthening is also offered and is the only option for Borosilicate glass. Heat strengthened glass will not dice but has more strength than non tempered glass.