Fluorescent is the obvious answer, but a search for 'fluorescent suit' brings up only workwear and hi-viz stuff. I think I'm looking for the name of the material that is highly reflective when under black light /ultraviolet.
Reflective material is made of a base cloth layer topped with micro glass beads and sometimes aluminum. Check these out: https://en.wikipedia.org/wiki/Retroreflector http://www.chinareflective.com/faqs/How_does_reflective_fabric_work.html
It looks like the same effect they used for Jor El's costume in the original superman. For that I think I remember reading that they used 3M reflective glass bead screen, which was basically what those old pull down projector screens are made of. To get the glowing effect they'd just shine a bright light at it. In your clip it looks like they used different coloured gels on the spot light to get a trippy light changing thing going on.
It could be a thin white cotton based on the image you have provided. While not as vibrant under the lighting, 100% Polyester is white will give off a good glow under a black light. Although you can use black light dyes on fabric to get them to glow brightly under such lighting.
Well I progressed beyond the scene which (that?) bore this question a long time ago, but thanks everyone. See, I told you the which/that rule won't sink in
Well, so long as you're sorted. You could have just used antifreeze, crushed vitamin B12 and any number of other very common household items that glow white, yellow or blue when illuminated by ultraviolet/back light.
