Light scattering by solutions of associating polymers at equilibrium

The intensity of zero-angle static Rayleigh light scattering by a polymer solution containing associated species, all in equilibrium with each other, can be calculated by introducing the thermodynamic condition for equilibrium either at the start or at the end of the calculation. Provided all species have the same value of the specific refractive index increment, it is shown for Flory-Huggins systems that the same formula is obtained by both routes. 9 refs