Atomic force microscopy was used to study the surface morphology of sol-gel derived Al2O3-TiO2-SiO2 coatings on microscope glasses. The coatings freshly annealed at 500 degrees C for 1 h were homogeneous on a nanoscale and showed typical glass pattern. After 10-month storage in air either before or after annealing, tetragonal-like crystallites were observed in coatings. The effects of chemical compositions and the storage process on the surface topography and the crystallization of anatase were studied and discussed in combination with the XRD results of corresponding annealed gels.