Is there any relation between Refractive index and density of a material? It is not found to be proportional in my experimental results. Is there any equation to relate these parameters?
I'm not sure about solids and liquids as they are almost incompressible, but for gases, it should be varying with pressure and temperature. Since gas density is also a function of pressure and temperature, I expect it to be a factor (See this article for example). I hope someone familiar can explain further.