Actually, I am studying alkali tellurites (both glasses and crystalline phases). In fact, the glass forming ability depends on the amount of modifier oxide in the tellurite network. Thus, I am wondering if there's any method that can be used to represent the degree of ease of glass formation in terms of the modifier oxide amount?
The commonly used methods for determining the of a glass forming ability and thermal stability are DTA and DSC. From determined Tg, Tx and Tm (Tl) You can calculate Kauzmann relationship (Trg=Tg/Tm>=0.67) and Hruby coefficient :k= Tx-Tg// m–Tx
The larger difference Tx-Tg and the smaller temperature interval Tm–Tx hamper the processes of crystallisation, and consequently facilitate glass formation.
see:
E. Lefterova, S. Bliznakov, P. Angelov, Y. Dimitriev, DSC FOR INVESTIGATION OF THERMAL STABILITY OF GLASSES, Advanced Techniques for Energy Sources Investigation and Testing, Sofia, Bulgaria, 4th 9th September 2004, http://www.bas.bg/cleps/poemes/workshops/Proceedings/Papers/P6_Lefterova.pdf
Y. Dimitriev, Y. Ivanova, M. Dimitrova E .D. Lefterova and P.V. Angelov, Glass Structure of the Ag2O TeO2 V2O5 System, J. Matt. Sci. Lett, 19 (2000) 1513-1516.
R. Iordanova, E. D. Lefterova, I. Uzunov, Y. Dimitriev, D. Klissurski, Non-isothermal Kinetics of Crystallization of V2O5-MoO3-Bi2O3 Glasses, J. Therm. anal. & Calorimetry 70 (2002) 393
and corresponding references
Thank you so much Elefteria Lefterova for your detailed answer !
You may also check the article below for the best parameters to gau
ge GFA. Good Luck!
Journal of Non-Crystalline Solids 351 (2005) 3296–3308
Can glass stability parameters infer glass forming ability?
Marcio L.F. Nascimento, Luciana A. Souza, Eduardo B. Ferreira,
Edgar D. Zanotto
Vitreous Materials Laboratory, Department of Materials Engineering, Federal University of Sao Carlos, Brazil (lamav.weebly.com)
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Glass-forming ability (GFA) is the easiness to vitrify a liquid on cooling, while
glass stability (GS) is the glass resistance against devitrification on heating; but it is questionable if there is any direct relationship between these two parameters. Therefore, to test this possibility, we assess and compare GFA and several GS parameters through quantitative criteria. GFA and GS were calculated for six
stoichiometric glass forming oxides that only present surface (heterogeneous) crystallization in laboratory time scales that, in addition to surface nucleation, also present homogeneous (internal) crystallization. We gauge GFA by the critical cooling rate, which was calculated from an estimated number of heterogeneous nucleation sites per unit surface and from experimental crystal growth rates...
Dear Mohammed, one suggestion to add to the already excellent answers posted, if you wanted to graphically depict ease of glass formation for each composition, you could also consider establishing TTT (Time Temperature Transformation) curves for each glass and plotting them all together on one graph. This is not for the faint-hearted though, it will take a considerable number of experiments and data points. I would suggest following the guidance above first...but this is another way you could perhaps achieve your aim. Kind Regards, Paul Bingham.
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