Implementation of Glass Transition Physics in Glass Molding Simulation

Abstract:

Glass transition is the most important factor in the thermo-forming of glass elements of precise geometries such as optical glass lenses. Among many attempts to model the physics of glass transition, the Master equations based on the potential energy landscape (PEL) appear to be apropos. In this study, we used Monte-Carlo approach to approximately solve the master equations and further implement the Monte-Carlo method in the finite element simulation. We used Selenium as an example since its PEL has been quantified. Through the FEM simulations, it is found that the geometrical replication quality is the best when the forming is performed at the viscosity around 10⁵~10⁶ Pa×s, that the residual stress developed in the cooling process can be minimized in the slow cooling process or through post-annealing process after moulding.

• Periodical: Advanced Materials Research (Volume 325)
• Pages: 707-712
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.325.707
• Online since: August 2011
• Authors: H.H. Ruan, Liang Chi Zhang
• Keywords: Finite Element Method (FEM), Glass Molding , Glass Transition, Monte-Carlo Simulation

References

[1] Angell CA. Formation of glasses from liquids and biopolymers. Science 1995; 267: (1924).

[2] Debenedetti PG, Stillinger FH. Supercooled liquids and the glass transition. Nature 2001; 410: 259.

DOI: 10.1038/35065704

[3] Su L, Chen Y, Yi AY, Klocke F, Pongs G. Refractive index variation in compression molding of precision glass optical components. Applied optics 2008; 47: 1662.

DOI: 10.1364/ao.47.001662

[4] Jain A, Yi AY. Finite element modeling of structural relaxation during annealing of a precision-molded glass lens. Journal of Manufacturing Science and Engineering 2006; 128: 683.

DOI: 10.1115/1.2163362

[5] Narayanaswamy S. A model of structural relaxation in glass. Journal of American Ceramic Society 1971; 54: 491.

[6] Scherer GW. Use of the Adam-Gibbs equation in the analysis of structural relaxation Journal of American Ceramic Society 1984; 67: 504.

[7] Goldstein M. Viscous liquids and the glass transition: a potential energy barrier picture. Journal of Chemical Physics 1969; 51: 3728.

DOI: 10.1063/1.1672587

[8] Stillinger FH, Weber TA. Dynamics of structural transitions in liquids. physical Review A 1983; 28: 2408.

[9] Stillinger FH, Weber TA. Hidden structure in liquids. physical Review A 1982; 52: 978.

[10] Mauro JC, Loucks RJ, Gupta PK. Metabasin approach for computing the master equation dynamics of systems with broken ergodicity. Journal of Physical Chemistry A 2007; 111: 7957.

DOI: 10.1021/jp0731194

[11] Mauro JC, Loucks RJ, Varshneya AK, Gupta PK. Enthalpy landscapes and the glass transition. Scientific Moldeing and Simulations 2008; 15: 241.

DOI: 10.1007/978-1-4020-9741-6_15

[12] Heuer A. Exploring the potential energy landscape of glass-forming systems: from inherent structures via metabasins to macroscopic transport. Journal of Physics: Condensed Matter 2008; 20: 373101.

DOI: 10.1088/0953-8984/20/37/373101

[13] Ruan HH, Zhang LC. A Monte-Carlo approach for modelling glass transition. Journal of American Ceramic Society 2011; Submitted.