UV-cured resin stays uncured until exposed to ultraviolet (UV) light, either from sunlight (such as with ding repair kits like 'Solarez'

or from UV lightbulbs (this is what my glasser uses).
Cure time is very fast and the board doesn't go off early. UV-curing resin was recognized by air quality managers in SoCal as clean because the fast cure means no VOC emissions. I like them for this reason, plus how bright white the boards are when they're done, much more so than standard resins.