What Causes the Blue Light in Triboluminescence?

[Redhat]

triboluminescence ??

I have a question regarding triboluminescence that I was hoping someone could help me with.

Late last night, in the dim light of my living room, I peeled open an envelope and noticed a quick flash of blue light from the area where the envelope’s adhesive was separating. This intrigued me so I turned out the lights, stuck the envelope’s flap back to the envelope and peeled it back again. I once again saw bright flashes of blue light from the quickly separated adhesive. I could repeat this several times.

This prompted me to try an experiment. I stuck some Scotch tape along a piece of clear Plexiglas, turned out the lights and quickly pulled it off. Once again I saw the blue flash of light along the separating adhesive although this time it was much less intense.

My question: Is this an example of triboluminescence ?

If so, what are the physical/chemical processes at work?

Thank you,
Redhat

 

[Mk]

Are you serious?? That is so weird. I don't know what to tell you.

 

[Redhat]

Yes I am serious. You can try the experiments for yourself. The envelopes were the kind with the sticky gum adhesive. You can peel them open without ripping them. And the Scotch tape was ... Scotch tape.

Do it in a totally dark place and for the best effect, let your eyes become dark adapted for a few minutes. Although when I first noticed the flashes there were lights on in the room.

A known example of triboluminescence is the flashes of light one can produce by crunching wintergreen lifesaver candies. It seems to me that the flashes caused by seperating adhesives could be a similar process.

 

[Astronuc]

http://scienceworld.wolfram.com/physics/Triboluminescence.html

The property that some materials become luminous upon being scratched, crushed, or rubbed. Examples of substances exhibiting triboluminescence include the minerals fluorite (CaF2), sphalerite (ZnS), and wintergreen LifeSavers!

Redhat, I think the phenomenon is the second kind mentioned in the Wolfram article

The second type is observed most frequently in sugars (including wintergreen Life Savers), and results from the breaking of certain bonds. This breakage creates free bonds, which immediately absorbs and ionize nitrogen from the atmosphere, producing a characteristic green or blue-green flash. Maple syrup sucrose produces an especially strong effect.

The flashes presumably occur when the molecular (or inter-molecular) bonds of the adhesive break.