Ultratransparent glass-ceramics: the structure factor and the quenching   of the Rayleigh scattering
  Glass-ceramics with nanocrystals present a transparency higher than that expected from the theory of Rayleigh scattering. This ultra-transparency is attributed to the spatial correlation of the nanoparticles. The structure factor is calculated for a simple model system, the random sequential addition of equal spheres, at different volume filling factor. The spatial correlation given by the constraint that particles cannot superimpose produces a diffraction peak with a low $S(q)$ in its low-$q$ tail, which is relevant for light scattering. The physical mechanism producing high transparency in glass-ceramics is demonstrated to be the low density fluctuation in the number of scatterers. 
M. Mattarelli, M. Montagna, P. Verrocchio