I've seen the transmission spectrum for Didymium lenses and they are not the best for glass working which is very high in IR rather than UV. There are better lenses.
However, the type of glass working in chemistry is what we call "lamp work"or "torch work" and it doesn't amount to much of a hazard compared to glass blowing from an open furnace like I used to do. I'd only require the spectrum be matched with the hazard for furnace glass blowing. I wrote a data sheet I give to glass blowers about this issue. If anyone is interested in a copy, send me a snail mail address and I'll kill a tree and put a copy in the mail.
Monona
Barry Ferm
Chemical Hygiene Officer
Biology &Chemistry Laboratory Coordinator
St. Ambrose University
(563) 333-6162
In a message dated 12/21/2011 3:58:24 PM Eastern Standard Time, FermBarretA@SAU.EDU writes:
Didymium glasses are the norm, and a must, for glass working, and are available in prescription lenses. Chemical splash goggles can be worn overthe didymium glasses when needed.