It's interesting to hear that there is a new style as I've done several prints using the old style and it's so lame that it only works for a few minutes after being exposed directly to bright light especially with how rough it is on the machine. It wore a groove through the hotend on my old Sidewinder X2 after using about a Kg to print a giant Lego skeleton.
Imagine how I feel when I see the old stuff. Yes, it is cheaper and for child toys why not. But frigging filament, signs etc.? Strontiumaluminate based stuff is just a different level. just compare them, the old ZnS based stuff fades SO fast you can barely see it in a time lapse.
From a chemical composition standpoint I couldn't tell you, but my off-the-cuff testing indicates that the glow remains visible for quite a few hours -- All night, in fact, though obviously tailing off in brightness considerably as time goes on.