Effects of annealing above Tg on the physical aging of quenched PLLA studied by modulated temperature FTIR
The effect of the annealing few degrees above the glass transition temperature (Tda = 62 C) on the physical aging (Tpa = 51 C) of amorphous quenched poly(L-lactide) is investigated by an implementation of variable temperature Fourier transform infrared (FTIR). By using a temperature program composed of a linear heating ramp superimposed to a temperature modulation (modulated temperature FTIR), the reversing and nonreversing intensity variation of selected bands, related to highenergy gg and low-energy gt conformers, is investigated.