hi
this is one of the sources I was getting my research for specification or suggestions for the covering of a uv chip
pure plexiglass was suggested
http://www.newton.dep.anl.gov/askasci/eng99/eng99272.htm
mick
Good stuff, thanks 
The problem still remains that UV may damage any sheet of plastic that is not UV stabilised. The problem is that any long chain molecules as is in polycarbonates will get damaged and the chains are broken with fragments leaving the plastic translucent rather than clear. Quartz glass is a good transmitter of UV and so is PE or Polyethylene but that will degrade too and is generally not clear but rather slightly opaque and scatters light. Getting the right material is difficult.
Is quarz the same as quarz glass I wonder? If so I can think of a source of nice flat pieces of quarz that would work well as windows.
That is what they use as the front window on some of the diodes - called quarz glass and the diode name has G in the suffix. It would be stable to UV as well. 
It made me think of the old clocks with the tubular glass surround and all the brass workings visible…
Niko
What UV sensor are you experimenting with ?? I have been able to find a source for the OKI UV sensor in the US.
Thanks
Cheers
MikeyM
Ops that should have been that am UNABLE to find the OKI UV sensor in the USA>
#-o
Cheers
MikeyM
I got some sglux diodes from Boston Electronics, looks like they have a better part now http://www.boselec.com/products/documents/sgluxEryCA10-2006.pdf. I’ll find the other info and pm you, it was a while ago…
Updated: Sensor link changed.
MichaelPT,
I am interested in this as well. Looks like it may be a better option that mine as its an all in one package.
How much was the chip?
Nice work by the way. Any refererences on where to get the plexiglass.
TokKiwi any idea where you get it in NZ?
SVW - I’ll try a search tomorrow from work. Just wondering if the moulding form of acrylic resin could be formed into a thin dome with a flat base for a weather seal. It is all part of the family but would need to be sure there was UV stability without a stabiliser! Perhaps even pressed out of a sheet, ahhh now we’re talking! More hot ideas to follow up…
TK
WOW! That is good! Thanks Niko, I’ll ask the industry here too and see about forming a shape, yes I know - flat is a shape… But you can only ask.
TK
I PM’d you.
Thanks - now I am heading in the right direction I hope!
TK
A data point for you. I tested a piece of 2.5 mm “regular” acrylic and it blocks 90-95% UV.
I have a request in to a plastics chemist’s site, I do remember that link in UK by Michael too, that I read. Its about formability too whether by thermoplastic means or casting etc… It looks like I need to buy that cheap family summer beach hand held UV meter - it may be inaccurate too but I just want it for a relative reference! If it gives “reasonable” values then that may be good for diode and circuit testing as well.
Aha! My website is back on line… 
You can form it if you heat it up, but the biggest challenge is getting the right stuff in the first place. Also don’t ignore the viewing angle issue.
I’m not sure… are you looking for some material to make a “canopy” for the UV sensor? Have you ever thought about PTFE (Teflon)? It is an excellent UV transmitter and acts as a diffuser to get a good cosine response. It’ easy to find in thin sheets or blocks, all you need to work it is a cutter or a sharp knife.
Luis
I recall you used teflon for your solar sensor, but I have not found easy or cheap sources here. Maybe I’m missing something, what kind of company are you buying it from, and what application is it being sold for?
Hard to know the USA market correspondence. It is used in industrial coating, insulation, low friction applications, I’ve found it at construction material stores.
Maybe any of these links can help you find it:
DuPont Licensed Industrial Applicator (LIA) Directory