| ABSTRACT: | INF
INFLUENCE OF THE STRUCTURAL RELAXATION ON THE INDENTATION BEHAVIOR OF
THE SURFACE OF SILICA OPTICAL FIBER
N. Gougeon, R. El Abdi, M. Poulain
Rennes1 University; Rennes; France.
Structural relaxation is a major characteristic of liquids and glasses. It relates to the structural
transformations induced by temperature changes and its kinetics is governed by viscosity. Vickers
indentations were performed on silica optical fibers subjected to water interaction by a hydrothermal
treatment. The observation of the Vickers impression provided direct evidence of a lateral displacement of
material of the fiber submitted to the hydrothermal treatment. This indentation behaviour is consistent with a
structural relaxation promoted by the water and the glass network interaction. It is suggested that the water
could acts as a modifier since the deformation combines the densification and the plastic flow of the
material. When the relaxed surface layer is chemically etched, the anomalous behavior of silica under
indentation is restored as the deformation is controlled only by densification. In the present work, we
obtained AFM images of Vickers impressions made on several optical silica fibers. It is the purpose of this
paper to examine the influence of the structural relaxation on the indentation behaviour of the surface of
silica optical fiber.
|