So this is a question from my mum who collects various types of glass - mainly depression era. We understand why uranium/vaseluine and various other types of glass glow under UV but we have been unsuccessful as to why some of the red glass turns opaque yellow. I have been unsuccessful with google so now I am turning to you folks with the big juicy brains to help me find the answer.
I haven’t heard of this particular color change. I’ll have to look into it. The classic color change is window glass going from clear to blue/purple under long irradiation with sunlight. This was due to a change in the charge state of manganese impurities in the glass. Michael Faraday was the first to investigate thisat the begining of the 19th century as a member of the Royal Society’s first committee on optical glass.
I have observed color changes in crystals with ultraviolet irradiation due to changes in the nature of defect centers in the crystal. Glass has defect centers, too, but they don’t tend to change color with UV irradiation. My guess is that the color change you observe is due to a change in the impurity ion needed for the red color, but I don’t know which that would be.
I don’t think the OP means the glass changes color, she just means it fluoresces yellow.
Yes. Sorry I didn’t make that clearer.
Sorry – I didn’t make the connection.
It’s undoubtedly the additive that makes the red color (or something invariably associted with it), but I don’t know what was used to make that red. There are a great many fluorescing species out there. I once made sulfur glass that was blue under normal light, but which glowed orange-yellow under UV illumination. It was the S[sub]2[/sub][sup]-[/sup] ions in the glass that did it. Other sulfor ions or molecules didn’t.
Red glass is usually made with Gold Chloride, and my (brief) research shows that it’s not fluorescent. But, there are probably a lot of other metals in this glass - it could be any of them.