The refractive indices of non-chopped and chopped films of cryolite, MgF₂ and mixed cryolite-MgF₂, which is higher than the bulk value, measured using spectro-photometer, ellipsometer and Abeles method are observed to be higher than corres-ponding bulk values. Chopped films show a higher refractive index than non-chopped films. The electron diffraction study shows a more amorphous structure for the chopped films. The major part played by chop-time seems to be in increasing the initial minute’s-scale aging rather than settling of ad-atoms during chop-time. The observed dispersion curve shows that some unknown material other than water gives an important aging effect.