1. Various Scale Levels of the Gel-to-Glass Transformation
- Author
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Ekatherina Mazurina, Alexy Krivda, Valery Zhizhenkov, Alexandre Chmel, and Victor Shashkin
- Subjects
Infrared ,Chemistry ,Silica gel ,Analytical chemistry ,Infrared spectroscopy ,Radius ,Atmospheric temperature range ,Condensed Matter::Soft Condensed Matter ,symbols.namesake ,chemistry.chemical_compound ,Chemical physics ,Brillouin scattering ,Materials Chemistry ,Ceramics and Composites ,symbols ,Raman spectroscopy ,Elastic modulus - Abstract
The gel-to-glass transition in SiO 2 xerogels prepared by inorganic sol-gel synthesis was studied. The evolution of the molecular structure is traced using the infrared and low-frequency Raman spectroscopy methods. The elastic moduli of the samples as well as the pore wall moduli at various stages of heat treatment are determined from the data on Brillouin scattering. The formation of monolithic glass on the macroscopic level manifests itself within a narrow temperature range by the dramatic increase of Young's modulus to the accepted value for fused silica. This phenomenon coincides with structural transformations on the molecular scale: (i) the definite correlation radius (the long-range order sphere) appears; (ii) local distortions of the silica network relax.
- Published
- 1993
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