Glass-transition temperature of water: a simulation study

Area of Science:

• Computational physics
• Materials science
• Physical chemistry

Background:

• The glass transition in water is crucial for understanding its unique properties.
• Distinguishing between standard and hyperquenched glassy states is essential.
• Previous estimates of water's glass transition temperature may require revision.

Purpose of the Study:

• To investigate the glass transition of water using advanced simulation techniques.
• To analyze the influence of cooling rates on glassy water structures.
• To determine the specific heat dependence on temperature for different water glass states.

Main Methods:

• Utilizing the extended simple point charge (ESPC) potential for water simulations.
• Generating glassy water configurations at varying cooling rates.
• Calculating the temperature-dependent specific heat of annealed glassy water samples.

Main Results:

• Observed a weak prepeak (shadow transition) and an intense glass transition peak in specific heat.
• These transitions occurred simultaneously in properly annealed samples.
• The simulation results suggest a higher glass transition temperature for water than the commonly accepted 136 K.

Conclusions:

• The study provides evidence for a higher glass transition temperature in water.
• The findings support the existence of distinct features in the specific heat related to the glass transition.
• Simulation results were compared with the Tool-Narayanaswamy-Moynihan phenomenological model.