The Kauzmann paradox at constant volume.

Area of Science:

• Thermodynamics
• Physical Chemistry
• Materials Science

Background:

• Understanding the thermodynamic properties of materials like o-terphenyl is crucial for predicting their behavior under different conditions.
• The Kauzmann temperature represents a theoretical point where excess entropy vanishes, offering insights into glass transitions.
• Previous studies often focused on isobaric heating; constant volume behavior requires further investigation.

Purpose of the Study:

• To calculate the entropy of o-terphenyl in liquid and crystalline states under constant volume heating.
• To compare constant volume heating behavior with existing isobaric data.
• To validate the significance of Kauzmann temperature extrapolation under varying conditions.

Main Methods:

• Calorimetric data at 0.1 MPa was utilized.
• Equation of state data was employed for calculations.
• Specific heat functional forms were analyzed for both heating conditions.

Main Results:

• Entropy was calculated for o-terphenyl across a temperature range of 250-310 K.
• Specific heat exhibited the same functional form under constant volume as under isobaric conditions.
• Excess entropy vanished at nearly identical Kauzmann temperatures for both heating methods.

Conclusions:

• Constant volume heating of o-terphenyl does not qualitatively differ from isobaric heating in terms of excess entropy.
• The findings reinforce the importance and predictive power of Kauzmann temperature extrapolations.
• This study provides confirmation for theoretical models of thermodynamic behavior in condensed matter.