We carry several glow-in-the-dark fabrics.
http://www.favoritefabric.com/cgi/co...&keywords=glow
I have not used any of them myself, but Avlyn (the manufacturer of several of them) says that you do need to expose the fabric to a light source to "charge it up", and that eventually the glow material will wash off the fabric.
So, to me, it means that it would be better to use it in a quilt (which gets washed occasionally) than in pajamas (which will be washed more frequently).
Hope this is of some help!