There have been numerous posts on other forums re glow-in-the-dark paints and the verdict is unanimous: they are worthless.
I tried it (a glow paint specifically marketed for gun sights) and they are right - worthless.
The paint will glow brightly for a few minutes if you place them under a bright light, but quickly dim from "glow" to "barely see".
For night sights, tritium is the only way to go. For brighter day sights some of the plastic light-pipe style sights are good. Otherwise, use model paint or nail polish in some light or bright color.