My OP was about putting a stretchy rubber GITD ring on the outside of the flashlight, but I couldn’t find any good ones.
I ended up doing what Slayer1 did and put a ring of GITD tape (glow side facing the LEDs, of course) behind the bezel. It’s OK but not exactly what I wanted. At least it is easy to quickly ‘charge’ the GITD material. I am concerned about the heat from the LEDs melting out the adhesive from the tape and causing a gooey mess (or fire) in the head of the light, since these lights get so hot, especially in turbo mode. I tend to not run too long with higher light output settings, so it hasn’t been a problem yet, but is a concern if I ever do let the light heat up for a longer period of time.
The tape I got glows quite brightly for a while but does lose the glow after an hour or so. Even with night-adapted vision, it is quite faint. I was hoping for a better material- I know the stuff they use for outlining emergency exit paths on commercial aircraft (and trains, retail stores, factories, etc) is pretty good (even after a long transatlantic flight, with up to 8 hours in darkness, the lines on the floor and the EXIT signs still glow pretty well).
I bought commercial glow in the dark tape from an industrial supplier and it’s still not quite as ‘glowy’ as I wanted. I wonder where the really glowy stuff comes from.
PS I did notice that Walmart sold GITD Duck brand tape but online reviews suggest it’s probably no better than the stuff I got.