Application of Thermophysical Methods for Oxide/Silicate Glasses

An brief overview of the selected thermo-physical measurements realized in the VILA laboratories for the glass industry and for the fundamental research of glass is presented. Among the routine measurements realized for the glass industry the thermodilatometry for measuring the glass transition temperature, and linear thermal expansion coefficients of glass and metastable glassforming melt are described in detail. The fact that the glass transition temperature is not a single valued physical quantity is stressed in connection with the measurement time temperature schedule. The probably most important quantity related to the glass production technology is the viscosity. Its measurement in the range extending ten orders of magnitude is described. The combination of the falling ball method, the rotation viscosimetry and the thermomechanical analysis is needed to cover the above viscosity range. Among the methods used in the fundamental research of glass structure and properties the study of structural relaxation is overviewed. Here the own method of combined viscous flow and structure relaxation TMA measurement is described in detail.

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PROPERTIES AND STRUCTURE OF Ag-DOPED As2Se3 GLASSES

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863507003524 ◽

2007 ◽

Vol 16 (01) ◽

pp. 49-57 ◽

Cited By ~ 6

Author(s):

CONGJI ZHA ◽

ANITA SMITH ◽

AMRITA PRASAD ◽

RONGPING WANG ◽

STEVE MADDEN ◽

...

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Raman Band ◽

Glass Structure ◽

Low Frequency ◽

Glass Network ◽

Scanning Calorimetry ◽

Covalent Bonds ◽

Frequency Shifts

Ag -doped As 2 Se 3 glasses were prepared by the melt-quenching method and the influence of silver doping on the glass structure and optical properties was studied using Raman and UV-Vis-IR spectroscopy and differential scanning calorimetry. For Ag concentrations less than 15 at%, introduction of Ag into As 2 Se 3 glasses mainly leads to the formation of Ag-Se covalent bonds, resulting in destruction of the glass network. This manifests itself by a decrease in the glass transition temperature and low frequency shifts in the As-Se Raman band. When the Ag concentration was higher than 25 at%, some Ag atoms exist in the glass matrix as coordinative bonds, resulting in a slight increase in the glass transition temperature and high frequency shifts in the Raman peaks. The relationship between the glass structure and properties is discussed.

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Thermal expansion of bulk amorphous Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy

Journal of Materials Research ◽

10.1557/jmr.1996.0232 ◽

1996 ◽

Vol 11 (7) ◽

pp. 1836-1841 ◽

Cited By ~ 15

Author(s):

Y. He ◽

R. B. Schwarz ◽

D. G. Mandrus

Keyword(s):

Heat Capacity ◽

Thermal Expansion ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Amorphous Alloy ◽

Crystallization Temperature ◽

Linear Thermal Expansion ◽

Undercooled Liquid ◽

Small Viscosity

The linear thermal expansion of the bulk amorphous Zr4.12Ti13.8Cu12 5Ni10Be22.5 (atomic percent) alloy has been measured from 80 K to 773 K. The data for T, Tg were fitted by a model based on the Grüneisen relation and a Debye expression for the heat capacity. From the fit, we deduced the Grüneisen parameter, g = 1.25, and the Debye temperature, QD = 400 K. Annealing the amorphous alloy at 663 K, which is between the glass transition temperature Tg = 623 K and the crystallization temperature Tx = 693 K, causes viscous flow in the sample. This is due to the small viscosity in the undercooled liquid.

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