What is the criterion to classify dishes as microwaveable ones? Whats the scientific reason behind this?
Microwaveable dishes are dishes which are not harmed by the microwave. Some plastic dishes are harmed because they would simply melt. For ceramic or glass dishes it’s more to do with whether they contain materials which would heat up at different rates. For example if you have a very thick part and a very thin part, it’s likely to be unsafe, since the stresses caused by heat expansion would be uneven. If your dishes are not marked, then if they seem to be standard glass or ceramic, and are of a fairly uniform thickness, then they may in fact be safe – try using one and check afterwards whether the heating pattern seems normal (no hotspots).
