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Glass is material with unknown atomic structure; even the definition of glass is not universally accepted. Glass structure is introduced by means of various geometrical and topological quantifiers. Models for oxide, organic, and chalcogenide glasses are explained, focusing on the most common glasses. The course also includes percolation models, experimental and computers method utilised for exploration of glass structure, and models for glass transition.
Last update: Pátková Vlasta (19.11.2018)
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Oral exam. Last update: Pátková Vlasta (19.11.2018)
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R: Zallen R.: The Physics of Amorphous Solids, John Wiley & Sons, 1983; R: Varshneya A. K.: Fundamentals of Inorganic Glasses, Academic Press, San Diego, 1994; A: selected papers and book chapters. Last update: Gedeon Ondrej (06.08.2024)
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Individual study and tutorials. Last update: Pátková Vlasta (19.11.2018)
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Non-crystalline solid state and glass. Formation of glass; quenching, condensation. Thermodynamic and kinetic conditions of glass formation. Structure, short-, medium-, and long-rang orders. Glass versus liquid. Glass transition, entropy, heat capacity; kinetics of glass transition.
Topology of glass. Short-range order, chemical bond, nearest neighbours, coordination number. Medium-range order, radial distribution function, rings, angle distribution. Long-range order. Glass network and dimension.
Chalcogenide glass. One- and two-dimensional solids. Degrees of freedom for chalcogenide and oxide glasses. Rule 8-n and ideal glass. Topological defects and changes in valence.
Organic glass. Random Coil and Random Walk models. Scaling exponents, fractal dimension.
Metal glass structure. Random Close Packing model, empirically obtained RCP structure.
Amorphous silicon and vitreous silica - Continuous Random Network model. Mathematical and chemical bonds - covalent graph, experimental and model RDF. Modifiers, Modified Random Network model.
Structure of silicate glass, alkali-silicate glass, silicate and alumino-silicate glass with alkali and alkali earth metal oxides, lead-silicate glass. Borate glass, alkali-borate glass, alkali-alumino-borate glassa. Germanium glass; germanium-silicate glass. Phosphate glass.
Percolation model, bond and site percolations. Cluster, cluster distribution, mean size, diameter. Percolation path, probability, threshold, critical exponents, scaling, fractals. Continuous percolation and critical volume.
Phase transition of type localization - delocalization. Free-volume model. Elektronic states in glass, phase transition metal - insulator; Anderson’s transition.
Modelling of structure of non-crystalline solids. Monte Carlo. Molecular dynamics.
Experimental methods for glass structure; X-ray and neutron diffraction; nuclear magnetic resonance; infrared and Raman spectroscopies; Mössbauer spektroskopy; electron paramagnetic spectroscopy; EXAFS, XANES. Last update: Pátková Vlasta (19.11.2018)
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Nejsou. Last update: Pátková Vlasta (19.11.2018)
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Students will be able to: describe methods of glass formation and glass transition, describe glass structure on the atomic level by means of various geometrical and topological quantifiers, select a suitable method for glass structure exploration. Last update: Pátková Vlasta (19.11.2018)
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