|MadSci Network: Physics|
Greetings, Herb! Well, you've certainly piqued my curiosity with this question! I believe what you are referring to is a change in the energy state of the electrons of your glow-in-the-dark material. You're looking at quantum mechanics in action! Glow-in-the-dark materials exhibit phosphorescence and florescence because their electrons become "excited" above their "ground" (lowest, "non-glowing") energy state, then give off light / heat as they return. The electrons in phosphorescent materials remain in a higher-energy "metastable" state for a time after excitation, slowly giving off their energy as the glow we see. ("Glow-in-the-dark" materials often mix florescent chemicals with phosphorescent chemicals to enhance brightness, color, etc.) Your laser probably doesn't have the power / frequency to excite the electrons from the ground state, but it's probably perfect for pushing metastable electrons "over the top" so they fall back down to their ground state. (Unless you have a REALLY powerful laser, in which case, you might be burning your target!) The following links will explain in a little more detail. If this doesn't describe what you've observed, or, if you have further questions, feel free to e-mail me at firstname.lastname@example.org . It sounds as if you've found something interesting I'd like to learn more about! Your MadSci, -Matt Links: General Concept: http://gmworld.newscientist.com/lastword/answers/ lwa499mysteries.html MadSci Archive answer: /cgi-bin/circR?/ posts/archives/apr99/925328634.Ph.
Try the links in the MadSci Library for more information on Physics.