On Sunday, 18 October 2020 09:25:03 UTC+1, Martin Brown wrote:


3M had a lovely little filament lamp based torch made of a dayglo
plastic doped with strontium aluminate which after daily exposure to
sunlight would glow for up to 8 hours. You could always find it in the
pitch dark - you could even see by its glow once dark adapted.
Unfortunately it failed to sell as people could not imagine how useful
it is to be able to find an emergency light in total darkness


You can readily buy the powder itself. Can then use it in, say, PVA and achieve all sorts of results.