Characterization of Etched Glass Surfaces by Wave Scattering
  The roughness of glass surfaces after different stages of etching is investigated by reflection measurements with a spectrophotometer, light scattering, and atomic-force microscopy (in small scale), and Talysurf (in large scale). The results suggest, there are three regimes during etching, according to their optical reflectivity and roughness. The first and second regimes are studied by the Kirchhoff theory and the third one is studied by the geometric theory. Also, we compare the roughness obtained by the optical scattering to the AFM results. 
G. R. Jafari, S. M. Mahdavi, A. Iraji zad and P. Kaghazchi