How Does a Glow Stick Work? Chemiluminescence

June 15, 2011

People always want to know how does a glow sticks work, so we are here to supply you with some answers!

Glow sticks give off light as a biproduct of a chemical reaction called chemiluminescence. This happens by mixing two liquids that, alone, cannot glow.

The chemicals inside the glow stick are a combination of a dye for coloring (usually either a sensitizer or a fluorophor) and what has been called Cyalume. Cyalume is also known as Bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl) oxalate (CPPO) which is a solid ester. The oxidation products are what causes the chemiluminescence (glow) in a glow stick.

So that's the short version.

But if you're adventurous and want to try to make it yourself, it can be done by reacting 2-carbopentoxy-3,5,6-trichlorophenol with oxalyl chloride.

The liquid in the capsule which is inside the plastic housing of the glow stick is just plain old Hydrogen Peroxide. This is the familiar stuff that you get from Walgreens or CVS. If you've ever noticed how it bubbles when it comes in contact with something then you'll know why it's the active ingrediant. When it mixes with the Cyalume it releases an Oxygen molecule that quickly forms Carbon Dioxide. This causes a releases of energy with new bonds being broken and formed. This release leads to the excitement of the electrons in the dyes causing what you see as Glow. When the glow fades, you know that the chemical reaction is finished and that the dye has released enough photons (energy in the form of light) to be stable.

But you don't have to take my word for it. Here's Anne Marie Helmenstine, Ph.D., who wrote on About.com :

"Specifically, the chemical reaction works like this: The hydrogen peroxide oxidizes the phenyl oxalate ester, to form phenol and an unstable peroxyacid ester. The unstable peroxyacid ester decomposes, resulting in phenol and a cyclic peroxy compound. The cyclic peroxy compound decomposes to carbon dioxide. This decomposition reaction releases the energy that excites the dye."

It should be noted that while different dyes cause the different colors, some chemical formulations are actually patented. Most importantly is the red dye formulation which is used in several different colored glows. If you've ever seen red plastic tubing used to make a red glow stick, then you know that you are buying from someone without the patent or license for that chemical formula. Just so you know where we got our information . . .

http://chemistry.about.com/od/howthingsworkfaqs/a/howlightsticks.htm http://en.wikipedia.org/wiki/Glow_stick http://www.howstuffworks.com/light-stick.htm

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