The glass used in the door of a microwave oven is typically made of a special type of glass called "safety glass" or "microwave-safe glass." This glass is designed to allow users to see the food while it is being heated or cooked inside the microwave, without exposing them to harmful microwaves.
The composition of microwave-safe glass includes materials that are transparent to microwave radiation and can withstand the heat and energy produced by the microwave oven. The glass is treated and specially manufactured to prevent cracking or shattering due to thermal stress or microwave exposure.
It's important to note that not all glass is microwave-safe. Regular glass containers or dishes, particularly those with metallic or reflective coatings, can cause arcing (sparks) and potentially damage the microwave or create a safety hazard. Therefore, it's essential to use only microwave-safe glassware and follow the manufacturer's guidelines and recommendations for safe microwave use. Always check the labels or markings on glass containers to ensure they are microwave-safe before using them in your microwave oven.