Glow in the dark glass has phosphorescence... meaning it contains a special substance called phosphor. Phosphors give off visible light after being energised. (This means that they have to soak up light for a while before they will glow!) Glow Glass uses strontium aluminate, which is a new phosphate that allows a "super" glow!

It stores about 10 times as much light as zinc sulphate (another type of phosphor used to create glow-in-the-dark items). As a result... the glow lasts longer!

For the strongest and longest-lasting glow, we recommend charging the glass with a UV light (blacklight) or placing it in direct sunlight.