For anyone still interested in more info on UV absorption by glass an other materials - Ben Krasnow, from Applied Science, just released quantitative results of his research on eyewear and sunscreen with a deuterium light source at https://youtu.be/vwsHRrDYu5o
Better to be safe then sorry
Thanks for this relevant information. From the safety aspect:
It demonstrates that to completely block UV, polycarbonate must be further coated. And glass is not really protective (attenuation by about 50% does not count in my opinion). Green plastic is better, I think it is being used by professional glass blowers. Or they use dark blue protective eyeglasses.From the illumination brightness aspect:
It demonstrates that there is a significant loss of UV beam intensity on passing through glass. And nearly total loss on passing through polycarbonate.From the purist aspect:
The loss of ~10% of the beam intensity when passing through SiO2 is possibly due to reflectance. Each surface of the plate might reflect 5%.