I know there's glow in the dark paint, and googling "glow in the dark marker" yielded lots of results. I imagine the glow 'wears off' of lots of these in a short time, but you'd have to look for product descriptions/reviews to see.
If there's a Michael's (large craft store) in your area, I assume it would be a good starting point.
As long as the text/background contrast is high, the sign is simple, the print is large, and the room isn't totally dark, you'll probably be okay...but a glowing sign would certainly be cooler
Good luck!