Glass formation in amorphous SiO2 as a percolation phase transition in a system of network defects

  title={Glass formation in amorphous SiO2 as a percolation phase transition in a system of network defects},
  author={Michael I. Ojovan},
  journal={Journal of Experimental and Theoretical Physics Letters},
  • M. I. Ojovan
  • Published 1 June 2004
  • Materials Science
  • Journal of Experimental and Theoretical Physics Letters
Thermodynamic parameters of defects (presumably, defective SiO molecules) in the network of amorphous SiO2 are obtained by analyzing the viscosity of the melt with the use of the Doremus model. The best agreement between the experimental data on viscosity and the calculations is achieved when the enthalpy and entropy of the defect formation in the amorphous SiO2 network are Hd=220 kJ/mol and Sd=16.13R, respectively. The analysis of the network defect concentration shows that, above the glass… 
On Structural Rearrangements Near the Glass Transition Temperature in Amorphous Silica
The formation of clusters was analyzed in a topologically disordered network of bonds of amorphous silica (SiO2) based on the Angell model of broken bonds termed configurons. It was shown that a
Topologically disordered systems at the glass transition
The thermodynamic approach to the viscosity and fragility of amorphous oxides was used to determine the topological characteristics of the disordered network-forming systems. Instead of the
Revealing Structural Changes at Glass Transition via Radial Distribution Functions.
A method to determine the glass transition temperature is proposed based on allocating Tg to the temperature when a sharp kink in FSDM occurs, which is more sensitive compared with empirical criterion of Wendt-Abraham.
Viscosity and Glass Transition in Amorphous Oxides
An overview is given of amorphous oxide materials viscosity and glass-liquid transition phenomena. The viscosity is a continuous function of temperature, whereas the glass-liquid transition is
Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships.
A direct anti-correlation between fragility ratio and configuron percolation threshold, which determines the glass transition temperature in the analysed materials, was found.
Radiation-Induced Fluidity and Glass-Liquid Transition in Irradiated Amorphous Materials - 9082
This paper describes the fl uidity behaviour of continuously irradiated glasses using the Congruent Bond Lattice model in which broken bonds – configurons –facilitate the flow. Irradiation breaks the
Glass: Kohlrausch exponent, fragility, anharmonicity
  • J. Rault
  • Materials Science
    The European physical journal. E, Soft matter
  • 2012
From various experiments and in agreement with predictions of this model it is concluded that the Grüneisen parameter γB (pressure derivative of the bulk modulus) and the Mean Square Displacement characterising the anharmonicity of solids (and liquids) are the main parameters which govern the relaxation properties of the glass state.


Distinguishing liquids from amorphous solids: Percolation analysis on the Voronoi network
The mutual arrangement of the Delaunay simplices (configurations of four nearest atoms) has been studied for molecular dynamic (MD) models of liquid and quenched rubidium obtained by M. Tanaka [J.
Viscosity of silica
Experimental measurements of the viscosity of silica (SiO2) are critically examined; the best measurements show an activation energy of 515 kJ/mole above 1400 °C and 720 kJ/mole below this
A Random Walk in Search of the Glass Transition
For thousands of years man has made glass and learned to shape it and colour it exquisitely. Some ancient civilisations invested its manufacture with ritual and mystery. Today, the mystery persists
Viscosity of network liquids within Doremus approach
Defect-mediated diffusion and viscous flow of network forming liquids have been investigated. An analytical formula of viscosity has been derived with two-exponential forms demonstrating high
Percolation, statistical topography, and transport in random media
A review of classical percolation theory is presented, with an emphasis on novel applications to statistical topography, turbulent diffusion, and heterogeneous media. Statistical topography involves