One of the dn/dT (-ve) polymers around is polyurethane. The most readily
available source of this is clear polyurethane household varnish (gloss
finish!). This can be diluted with xylene, and filtered to make excellent
waveguides. Waveguides are fabricated by spin coating the solution onto a
substrate with an appropriate refractive index (BK-7 is close to PUR, and
makes for easy thermal mode extinction).

Try looking at the following references.

K.H. Cazzini, F. R. Akkari, W.J. Blau, " Thermooptic mode extinction
modulation in polymeric waveguides", J. Non-Cryst. Solids,  187,  1995

K.H. Cazzini, F.Z. Henari, F. Akkari and W.J. Blau "Experimental Observation
of Dark Spatial Solutions in a Planar Polymer Waveguide", Photonic Science
News 4 1999 5-7

K.H. Cazzini, F. R. Akkari, W.J. Blau, " Thermooptic mode deflection
switching in polymeric optical waveguides", Proc. Quantum Electronics
Conference 11, 1993, Queens University, Belfast.

K.H. Cazzini, F.R. Akkari, W. Blau , " A Novel Integrated Optical Microphone
utilising the Thermooptic Effect in Polymers ", Sensors and their
Applications VII. Proceedings of the Seventh Conference on Sensors and their
Applications, Institute of Physics Publishing, Bristol, 1995, pp.131-4

Sincerely,

Karl H. Cazzini (Ph.D)
Senior Scientist
Alcon Research Ltd.


----- Original Message -----
From: "cortese" 
To: 
Sent: Tuesday, June 25, 2002 1:48 PM
Subject: [mems-talk] Thermo-optic polymers


> Hi
> I'm looking for commercial polymers with high thermo-optic coefficient.
> In other terms with an high dn/dt.Could anyone suggest me where to buy
them
> or where to find  detailed informations about them?
> Best Regards
> Mario
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