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Generalphosphorescent Chlorophane

9th Oct 2019 14:13 BSTMichael L Otto

I collected quite a bit of Chlorophane about ten years ago from Old Mine Plaza(Home depot) construction site Trumbull, Ct USA. I kept it in the dark(10 yrs) and tested it with a 365nm long wave UV light last night. I was surprised to see it was still glowing(light green) 10 hours later before daylight came. How unusual is it to glow that long? 

9th Oct 2019 14:58 BSTKyle Bayliff

One of the unique properties of chlorophane in addition to fluorescence is thermoluminescence. Is your sample stored in a warm place or have you been handling it a lot? The effect can be fairly long lived even after the heat source is removed.

9th Oct 2019 20:02 BSTMichael L Otto

The Chlorophane I collected is fluorescent, thermoluminescent and phosphorescent. It does turn bright blue on the stove at high temps also. I was posting about it's very long phosphorescence after exposure to a long wave UV light. This wasn't caused by handling.

10th Oct 2019 00:38 BSTKyle Bayliff

I don't really have a better answer for you, but if you repeat the experiment, post some pictures and measure exactly how long the phosphorescence persists. It is strange that it would persist for that long without some continuous excitation.

10th Oct 2019 00:42 BSTKyle Bayliff

Oh, the other factor that would matter is how long you exposed it to the UV lamp. If you repeat, I would measure that, too.

10th Oct 2019 12:39 BSTMichael L Otto

I exposed the 3cm x 2cm pieces to 10 seconds of 365 nm long wave UV light(grey Convoy S2 "flashlight") from 2 inches away from the light. I did this at 10:30 pm Tuesday. Wednesday morning 7am I placed them under my bed on a magazine.  Thursday 3am I pulled them out and they were still glowing. That's 28 1/2 hours! The room's temp was 60-65 degrees F. I also held one different piece in my clenched fist for 10 minutes and it glowed faintly from my body heat.

10th Oct 2019 12:23 BSTHarold Moritz Expert

Chlorophane is noted for all these properties, so what you see is not unusual, that's what defines the variety. Beware that after you heat a piece it will lose all these properties and act like regular fluorite with only blue-purple fluorescence under all UV wavelengths. See details in Fluorescence by Manuel Robbins, 1994.
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