Resistance to rapid temperature variations is particularly important in the case of pharmaceutical or food contact containers meant to be filled with hot/cold liquids (e.g. tomato sauce), or to undergo thermal cycles of pasteurization, sterilization or freeze-drying (lyophilization), or for the kitchen tableware.

The test for the determination of the resistance to thermal shock is carried out by completely immersing the glass articles in thermostatic tanks containing hot water (hot bath) or cold water (cold bath), and moving them quickly and repeatedly from one to the other according to a pre-established time schedule; the greater the number of cycles withstood without breakage and/or the greater the temperature difference between the two tanks necessary to break the samples, the greater the resistance to thermal shock of the articles.

By appropriately regulating the temperatures and the test times, the test can be carried out in accordance with method B of the UNI 9303:1988 standard Glass containers. Test of resistance to temperature changes, or according to UNI EN ISO 7459:2004 Glass containers. Resistance and durability to thermal shock, or ASTM C 149-86 Standard Test Methods for Thermal Shock Resistance of Glass Containers.

In the case of borosilicate glass articles or those that have undergone a toughening treatment, generally resistant to temperature differences of more than 90 °C, the test is carried out according to method A of UNI 9303, which prescribes the use of a muffle oven instead of a hot bath.