| Light Stick Colors | |
There are several chemiluminescent chemical reactions, but the luminol and oxalate reactions are most commonly used for light sticks and glow sticks. American Cyanamid's Cyalume light sticks are based on the reaction of bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl)oxalate (CPPO) with hydrogen peroxide. The fluorophors (FLR) in this reaction are the chemicals that provide the color of the light stick.
A similar reaction occurs with bis(2,4,6-trichlorophenyl)oxlate (TCPO) with hydrogen peroxide:
These are some fluorescent dyes that may be added to light sticks to release colored light:
| Blue | 9,10-diphenylanthracene |
| Green | 9,10-bis(phenylethynyl)anthracene |
| Yellow | 1-chloro-9,10-bis(phenylethynyl)anthracene Rubrene |
| Orange | 5,12-bis(phenylethynyl)-naphthacene Rhodamine 6G |
| Red | Rhodamine B |
Although red fluorophors such as Rhodamine B are available, red-emitting light sticks tend not to use them in the oxalate reaction. The red fluorophors are not very stable when stored with the other chemicals in the light sticks. Instead, a fluorescent red pigment is molded into the plastic tube that encases the light stick chemicals. The red-emitting pigment absorbs the light from the high yield (bright) yellow reaction and re-emits it as red. This results in a red light stick that is approximately twice as bright as it would have been had the light stick used the red fluorophor in the solution.
