To examine the phenomenon of polarization memory, we examine time resolved backscattering of circularly polarized plane waves normally incident on a slab containing a random distribution of latex spheres in water. For large spheres polarization memory occurs a short time after first order scattering and before depolarization. It is the result of successive near forward scattering events that maintain the incident wave's helicity. For moderately large scatterers, it exhibits a simple dependence on the anisotropy factor. For larger spheres or those with higher refractive indices, it also depends on complicated angular and polarization characteristics of backscattering given by Mie theory.