  Using atomistic computer simulations we determine the roughness and
topographical features of melt-formed (MS) and fracture surfaces (FS) of oxide
glasses. We find that the topography of the MS is described well by the frozen
capillary wave theory. The FS are significant rougher than the MS and depend
strongly on glass composition. The height-height correlation function for the
FS shows an unexpected logarithmic dependence on distance, in contrast to the
power-law found in experiments. We thus conclude that on length scales less
than 10 nm FS are not self-affine fractals.
