Isoconversional kinetics of glass aging

Area of Science:

• Materials Science
• Physical Chemistry
• Polymer Science

Background:

• Maltitol glass exhibits enthalpy relaxation, a crucial phenomenon in glassy materials.
• Understanding relaxation dynamics is key to predicting material properties and stability.

Purpose of the Study:

• To investigate the enthalpy relaxation process in maltitol glass using differential scanning calorimetry.
• To analyze the kinetics and activation energy of relaxation at different aging stages.

Main Methods:

• Differential scanning calorimetry (DSC) was employed to measure enthalpy relaxation.
• Isoconversional kinetic analysis was used to determine activation energies.
• Temperature dependence studies were conducted to estimate aging rates.

Main Results:

• Effective activation energy significantly increases from glassy to supercooled liquid state.
• Early aging stages show activation energy around 117 kJ/mol, smaller than alpha-relaxation (413 kJ/mol).
• Later aging stages approach the alpha-relaxation activation energy, with initial aging rates yielding 60-80 kJ/mol.

Conclusions:

• The effective activation energy for early aging stages approaches beta-relaxation values.
• The study elucidates the complex kinetic transitions during maltitol glass aging.
• Findings contribute to understanding relaxation mechanisms in amorphous solids.