Thermal shock is one of the primary reasons dinner glassware cracks or breaks. Glass takes on the temperature of the liquid it holds and/or the temperature of whatever is closest to it (i.e., a warm oven, ice sculpture, etc.). It takes the glass item some time to adjust to a new temperature. therefore, don't put your glassware through extremes. Glasses that have held ice or cold liquids should not be immediately washed in hot water. (This works in reverse as well, hot to cold.) Begin washing the glassware in room temperature water or something closer to its most recent temperature.