Volume scattering properties of glass particles as a function of size and absorption coefficient

The albedo and nadir incident polarized BRDF were measured at λ=633 nm for five different Schott glasses. Measurements were acquired using a polarized goniometer and a Minolta spectrophotometer. The Schott glass samples were in the form of particles which were obtained by crushing Schott glass plates with known absorption coefficient and index of refraction. The particles were sieved into five different particle size distributions (i.e., bin sizes). A total of 25 different absorption coefficient-bin size combinations were obtained. Data is reported in the form of albedo and depolarization ratio as a function of absorption coefficient and mean bin size. Comparisons are made between albedos measured using the spectrophotometer and those approximated by averaging directional reflectance data over all view angles in the principle plane. It is shown that a close relationship exists between albedo and nadir only backscatter measurements and hence it is possible to estimate albedo with a single measurement at nadir. Also, an empirical factor relating depolarization ratio to individual particle diameter and absorption coefficient is developed which serves as a convenient way to estimate depolarization ratio