Or and I've been meaning to try this just cause I want to know. You could try mixing the Acrylic based glow paint into a translusent blue,green whatever colour your going for. It's a cheap way to go if it works.
I would take a "blurry" sheet of plastic, roll it up into the inside, take a simple battery, blue led and all that good stuff and stuff it inside the breather.
so it shines for a very long time, you can turn it on and off and it will look very cool
i have thought about that, but i already found fluorising paint(IN A CAN!) so i dont have to spray it, well, all idea's were very handy, maybe you could apply them if you buy a re-breather i will mold (subliminal message intended.
Now that stuff looks cool! That stuff might work AND you can choose your color! The aqua might work for the grunt.
Also, there was a type of neon wire light that I had bought for use in my truck I used to have when I was customizing the interior and wiring up neons in it. I bought the blue color, but when it lights up, the color looks a little like the color used on the grunts. I had bought it years ago, but I think they are still available.
And as for what cardboardwizard said, I think it's that EL wire stuff. I'm not totally sure about that though. XD
PM noodle I'm sure she'll help if she can. I too think it's the camera reflection on the light blue paint. And it could easily be done with the plexiglass and some LEDs. There are ways of making luminescent paints but the chemical processes are really involved and not as cost effective as a $5 clear PVC pipe, a $1 worth of wire and a couple $.03 LEDs.
Also, if you are willing to play with toxic materials, you can open a glow stick and "paint" it as needed. You must paint it in near zero temperatures so not to waste valuable glow time. Not a problem in the winter
Just keep the costume pieces cold until you are ready to wear them.
Poke small holes and add a couple LEDs to make it glow... But the holes would need to be super small like pin sized or something around there, good luck...