Glow in the dark toys seem to have sprouted anywhere from glow sticks and star stickers to glow in the dark posters, and even glow in the dark clothes! At least you would be easy to find at night.

But what makes those fun glow in the dark novelties…well…glow? If you own any of these products or have had fun with them in the past, you are well aware that anything glow in the dark has to be “charged.” This is usually done by holding them to a light, where you can then take them into a dark room and enjoy their glorious glow in the dark radiance, for up to ten minutes, anyway.

All glow in the dark products contain phosphors. A phosphor is a substance that emits visible light when energized. Phosphorescent materials continue to glow even after their energy source (light) has disappeared or has been removed. We see phosphor products everyday, even if we’re not aware of it. For example, some of the main places we see phosphors is in television screens, computer monitors and florescent lights.

In order to make a glow in the dark toy, it would require phosphor that is energized by normal light and has a long resolution. Two phosphors that have these characteristics are zinc sulfide and strontium aluminate. Strontium aluminate is newer and it’s what you see in the “super” glow in the dark toys, toys that can glow in the dark for over an hour. It has a much longer persistence than zinc sulfide does. The phosphor is mixed into a plastic and molded to make most glow in the dark merchandise.