How do you get the MAM Night Ulti Glow pacifier to glow?

I recently purchased a pack of the MAM glow in the dark pacifiers because my baby is always waking up in the middle of the night crying for her binky and we can never find it without turning the light on. There were no directions in the package, nothing online, and we can't figure out what we're doing wrong. We've held the paci up to a light for several minutes, and only get about 1 minute of faint glow out of it. Has anyone had any luck getting this thing to work? Are we supposed to keep it under a light for several hours? Thanks!