No, it is generally not safe to put glass cookware in the microwave oven or over an open flame unless it is specifically labeled as microwave-safe or flameproof.
Microwave Oven: Most glass cookware is not designed for use in a microwave oven. When you microwave regular glass, it can heat unevenly, leading to potential breakage or shattering. Microwave-safe glassware is made with special heat-resistant glass that can withstand the rapid heating and cooling cycles of a microwave without breaking.
Open Flame: Glass cookware is not suitable for use directly over an open flame, such as on a stovetop or campfire. Glass has poor thermal shock resistance, meaning it cannot handle sudden and extreme changes in temperature. Placing glass cookware over an open flame can cause it to crack or shatter due to the intense heat.
If you need to use glass cookware in the microwave or on the stovetop, make sure to check the manufacturer's instructions and labeling. Some types of glass cookware, such as Pyrex or borosilicate glass, are designed to be microwave-safe and can handle higher temperatures. However, even with microwave-safe glass, it's essential to follow the guidelines provided by the manufacturer to prevent accidents and ensure the longevity of the cookware.
For stovetop cooking or open flame use, it is better to use cookware made from materials specifically designed for these purposes, such as stainless steel, cast iron, or certain types of ceramic cookware that are labeled as flameproof. Always read the cookware's instructions and limitations before using it to ensure safe and effective cooking.