“…Some monitored material dilatation by measuring variation of free volume size and distribution due to loading [25,26,27,28,29,30,31]. Others examined distortion by inferring chain reorientation and changes in side group concentration from infrared spectra [32,33,34]. At the point of incipient rupture, still others used a combination of techniques to identify correlations among bond scissions, radical concentration, and crack nucleation [35,36,37,38].…”