![]() ![]() We have also been successful with Windows XP Version 2002, Service Pack 2 using Firefox2.0.0.14 and Internet Explorer. ![]() ![]() Matlab© scripts for the calculations can be downloaded from this ftp site.įirst, this version of the calculator has been tested successfully in OS X 10.4.11 (Tiger) with browsers Safari 3.1.1 and Firefox2.0.0.14, cutting and pasting from TextEdit.app. ![]() Low values of m correspond to strong (Arrhenian-like) melts and higher values of m indicate increasing fragility (non-Arrhenian).įurther details on the calculations are available in the PDF file: Viscosity tutorial.Īn Excel spreadsheet file can be dowloaded here: grdViscosity.xls. Essentially, it is the slope of the viscosity trace taken at T g and can be calculated as: where B, C and T g are specific properties of the individual melts (e.g., rhyolite vs. The "steepnessindex" ( m), as defined by Plazek and Ngai, is a common measure of melt fragility used to track departures from Arrhenianbehaviour and to distinguish strong and fragile melts. Conversely, "fragile" liquids show non-Arrheniantemperature dependence indicating that thermal perturbations are accommodated by continuous changes in melt structure. "Strong" liquids show near-Arrhenian temperature dependence and show afirm resistance to structural change, even over large temperature variations. Melt fragility is a measure of the sensitivity of liquid structure and flow properties to changes in temperature and it distinguishes twoextreme behaviours of glass forming liquids: strong vs. T gis the temperature separating the liquid (relaxed) from the glassy(unrelaxed) state and is taken here as the temperature corresponding toa viscosity of 10 12 Pa-s. The viscosity model can be used to compute derivative transportproperties of glass-forming materials, such as the glass transitiontemperature ( T g) and the fragility ( m) of silicate melts. Dissolved volatile contents vary from about 0 to 8 wt% H 2O and 0 to 4 wt% F. The multicomponent model is calibrated on melt compositions spanning oxide contents (wt.
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