CYALUME® lightsticks, manufactured by American Cyanamid Co., and similar items available from other manufacturers, are devices that produce a “cool-light” by means of a chemical reaction. The reaction is similar to the one that produces light in a firefly, but the chemicals involved are different.  A lightstick consists of dilute hydrogen peroxide solution in a phthalic ester solvent contained in a thin glass ampoule which is surrounded by a solution containing a phenyl oxalate ester and the fluorescent dye 9,10-bis(phenylethynyl)anthracene, (blue lightsticks use 9,10-diphenylanthracene) all contained in a plastic tubular container.  
When the glass ampoule is broken, by bending the lightstick, the hydrogen peroxide and the phenyl oxalate ester react to form phenol and some intermediate (short lived) compounds. During the reaction, the energy given off is transferred to the dye molecules.  The excited dye molecules (designated as Dye®) give off the excess energy in the form of light without any noticeable heat.  Thus the name, “cool-light”.

Lightsticks can be used to demonstrate how the rate of a chemical reaction varies with temperature. To do this, initiate three lightsticks. Place one lightstick in ice water, one in hot tap water (not boiling), and leave one at room temperature as a control. The effect of temperature on the reaction can be observed within a few minutes.
Lightsticks are used as emergency lights and safety lights in industry and for camping. As toys, they are made in the form of earrings, necklaces, bracelets, rings, eyeglasses, and bowties. They are also used to light up balls, golf balls, and flying disks for nighttime playing.

A recent variation of lightsticks are Magic in the Night® light shapes. These are adhesive backed packets in various shapes, such as circles, diamonds, and stars, and filled with lightstick chemicals which are stored in separate glass ampoules. Both ampoules must be broken in order to mix the chemicals.

Lightsticks are dated to indicate their life time. If stored in a cool place, they remain active for at least one year past that date. Light shapes have no expiration date.

The description above was taken from Chemistry in the Toy Store and used with the permission of the author David A. Katz.
Graphic is from  Shakhashiri, Chemical Demonstrations, Vol. 1, Univ. Wisconsin Press, 1983

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