A simple method for determination of the reflection coefficient at the internal surfaces of turbid slabs

The total reflectance of a slab turbid material is measured with an integrating sphere. Each slab was measured with a glossy and diffusing (etched) rear surface, both with and without a fully reflecting pill placed behind it. Formulae derived show that the results, together with the refractive index, permit calculation of the reflectance of the parity diffuse radiation at the internal rear surface. The method is applied to human dental enamel.