Influence of high pressure on the specific heat of amorphous polymers at low temperatures

Abstract

The specific heat c p of amorphous polycarbonate and amorphous polystyrene has been measured at pressures up to p=0.7 GPa in the temperature range 0.2 K < T<300 K. The specific heat shows a visible dependence on pressure, specifically in the temperature range at and below the typical maximum of c p / T 3. With increased pressure, the temperature T max of the c p -maximum and the temperature T min of the c p -minimum are slightly shifted to higher values. This is an indication that the energy spectrum of the low-energy vibrations shifts to higher energies with increased pressure.