Index of Refraction: Most Dynamic Substance

[Erkenbrand]

Well, once again, I ask something about index of refraction.
What is the substance that suffers the greatest change in density when heated/cooled (so that by heating it up only a few degrees its index of refraction will change, even if just by a tiny bit)?

 

[Danger]

I have some plastic at home for modelling things. It becomes extremely pliant in hot water (below boiling), so I expect that its I of R changes significantly. Mine isn't transparent, though, so I can't test it. Gelatin dissolved in hot water changes as it cools. Since the electronic structure of piezo crystals changes under pressure, perhaps it their I of R does too. Egg white definitely becomes opaque as you cook it, so other protein structures should as well. Maybe grab a cornea from a dissected frog and give it a shot.

By the way, though... it gets a little confusing having parallel threads on essentially the same topic. It will be easier for all concerned if you integrate them.

 

[Claude Bile]

Materials that exhibit a large refractive index change with temperature are generally termed Thermo-optic materials. Polymers in general, have the highest refractive index change with temperature, however they are highly birefringent compared to glass.

Claude.

 

[Erkenbrand]

Thanks guys!