Molecular dynamics simulation on devitrification: isothermal devitrification and thermodynamics of PbF2 glasses

Area of Science:

• Materials Science
• Solid State Chemistry
• Computational Materials Science

Background:

• Vitrification and devitrification are critical processes in glass science.
• Lead fluoride glasses exhibit unique ionic conduction properties.
• Understanding thermal history effects is crucial for controlling glass structure and properties.

Purpose of the Study:

• To investigate the vitrification and devitrification behaviors of lead fluoride.
• To determine the influence of heating rate on devitrification temperature.
• To analyze the dependence of glass properties on cooling rates (thermal history).

Main Methods:

• Molecular dynamic simulations were employed.
• Simulations covered vitrification and devitrification processes.
• Analysis included diffusion coefficients and structural organization during heat treatment.

Main Results:

• Different glass properties were obtained with varying cooling rates.
• Defects in the glassy matrix facilitate transitions to a superionic state with high fluorine mobility.
• Fast cooling led to single-crystal devitrification, while slower cooling resulted in multi-plane crystalline structures.

Conclusions:

• Thermal history significantly impacts lead fluoride glass structure and devitrification.
• High fluorine mobility in the superionic state is linked to anionic conduction.
• Controlled cooling rates can dictate the crystalline phases formed during devitrification.