This. That's what I read from Crash's request as well. Problem is, do we really want to have the cheapest overseas labor trying to paint the inside of a dome with hazardous phosphors (evenly) and then attempt to completely seal it so none of the coating comes out? We know how good they do soldering, crimping and gluing currently

Perhaps they have made phosphors that are less dangerous that what were on TV's in the recent past, but I fear that we'd see a repeat of the radium clock hand factories of a hundred years ago with something that would have the functionality that Crash is requesting.

If you want a quick half bright decay, followed by a very slow to 0, you could coat the inside of a dome with the glow in the dark paint and have it placed on a UV bulb. Problem is they only glow in the typical light green, so you'd also first have to stain the dome with some type of color to shift it correctly. Something to at least play around with, but not exactly the effect wanted since it drops so fast initially when the UV is removed.