  Metrological AFM measurements are performed on the silica glass interfaces of
photonic band-gap fibres and hollow capillaries. The freezing of attenuated
out-of-equilibrium capillary waves during the drawing process is shown to
result in a reduced surface roughness. The roughness attenuation with respect
to the expected thermodynamical limit is determined to vary with the drawing
stress following a power law. A striking anisotropic character of the height
correlation is observed: glass surfaces thus retain a structural record of the
direction of the flow to which the liquid was submitted.
