Spinodal decomposition in a binary fluid.

Light scattering has been used to study a mixture of 3-methylpentane and nitroethane undergoing spinodal decomposition. The scattered intensity has been measured in absolute units allowing the first test or theory with no adjustable parameters. The measured structure factor does not evolve according to theory even when the initial fluctuations are taken into account. We believe the reason is that the evolving concentration field causes the sample temperature to change continuously throughout the decomposition process