As a follow up to my ICON chat post on 7/01/24, here is an example of the effect of different UV wavelengths on glass.

In the first frame is the insulator under natural light. The second frame is under SW (shortwave) UV light, the third frame is under MW (midwave) UV light, and the fourth frame is under LW (longwave) UV light.

The center two pieces have virtually no reaction other than a hazy circular reflection of the flashlight on the skirt. The fourth frame lights up like pieces many have commented on.

While much of the discussion has centered on purple glass, other colors react as well. I have electric and peacock blue H.G. 162's which react with yellow green under LW UV, for example.

For clarification, I am unaware of any science that short term exposure to these light sources produces any discernible change to the glass like other forms of irradiation.