Between 220 - 300 nm, C-H bonds have high transparency.  Optical
absorption in this region by organic compounds, such as organic
polymers, is usually due to the presence of unsaturated covalent bonds,
such as CC double bonds, carbonyl groups (C=O) and various aromatic
rings (penyl or larger groups).

Simple alkane liquids (such as hexane) are excellent solvents for
spectroscopy in this region.  Acrylics contain carbonyl groups; styrenes
contain phenyl groups, for example.  Also, UV transparency is improved
by careful attention to removing UV absorbing impurities such as
polymerization initiators and plasticizers.

An interesting exception is the family of polyphosphazene polymers,
which are based on -P=N- polymer backbone and have good UV transmission
and high resistance to deep UV radiation damage.  They were once a
popular research subject, but I would be interested to know if any
commercial polyphosphazene products are available.

Don Friedrich
JDSU - Advanced Optical Technologies
Santa Rosa, CA
[email protected]

-----Original Message-----
From: Shay Kaplan [mailto:[email protected]]
Sent: Wednesday, March 25, 2009 5:57 AM
To: [email protected]; 'General MEMS discussion'
Subject: Re: [mems-talk] polymer which has transmission in UV

Kamlesh

Since polymers are base on CH bonds that have high absorptions bellow
300nm,
I'm afraid it would be hard to find such a material.

Shay