Known for its popularity everywhere from nightclubs to Disneyland, glow in the dark jewelry serves a variety of purposes. This jewelry can be used simply as decoration or as a safety device for children on Halloween. There are two basic methods used to make the jewelry glow.
Some glow in the dark jewelry uses the same technology as glow sticks in order to produce the glowing effect. These types of jewelry come in the form of bracelets or necklaces. The jewelry is constructed of a long plastic tube, bent into a circle to function as a bracelet or necklace. The tube contains a mixture of phenyl oxlyate and a fluorescent dye. Inside the tube is a smaller glass tube containing hydrogen peroxide. When the necklace is bent, or "snapped", the inner glass tube breaks, and the hydrogen peroxide and phenyl oxylate mix together -- the resulting chemical reaction produces energy in the form of light. The color of the fluorescent dye determines the color of the glow in the dark jewelry.
Once broken, glow necklaces or bracelets cannot be turned off. The glowing effect will last for several hours, but the outside temperature can affect the life of the jewelry. For example, placing glow in the dark jewelry in the freezer will make it last longer, while a warmer outside temperature will cause the jewelry to glow brighter but have a shorter life.
Unlike the chemical reaction which causes necklaces and bracelets to glow, other types of glow in the dark jewelry achieve this effect with a battery-powered LED light. The LED light is attached to the jewelry backing and can be made into rings, pins, or earrings. This setup is also used for body jewelry, such as tongue rings or navel rings.
The LED light used for glow in the dark jewelry flashes on and off, creating a strobe effect that is very popular at clubs and parties. The light is placed inside a plastic or glass casing that often has designs which may include happy faces, flowers, and hearts. When the battery dies, it can be replaced, making this type of glow jewelry much more durable than the chemical-powered type.
Sarah is a freelance writer living in Istanbul, Turkey, where she has taught numerous English language courses and runs a blog focusing on the expat community. Since joining the WiseGEEK team several years ago, Sarah has become a veritable fount of knowledge on many obscure topics. She has a B. A from the University of Oregon, where she majored in Romance Languages (Spanish and Italian) and Linguistics and an M.A. in TESOL from the Middlebury Institute of International Studies at Monterey.