What (non toxic) light sensitive materials do not burn away at high heat?
There are a number of types of photosensitive glass which change in appearance and chemical reactivity upon exposure, and of photochromic glass, which undergoes reversible change in color with radiation.
If you are using this as a surface applique on ceramic, one key factor would be having therml expansion coefficient compatible with the ceramic, or the object will crack on cooling. Consult the literature from a manufacturer, such as Schott or AZO Materials.
There are also techniques for making a photosensitive layer on ceramics, such as Pyrofoto, that do not involve applying glass. A small Pyrofoto kit is ~US$20.
BTW, you might find that microwave oven kiln adapters do not reach high enough temperature to be useful in this work -- literature states a limit of ~900°C, cone 010.