There is a clear agreement between the data obtained from all techniques in both the temperatures of the glass transitions and the relative change in the three regions that are typically at-Fig. (a) Experimental variable-temperature data from THz-TDS, FTIR, BLS , DMA, and theoretical AIMD-simulated volume for amorphous sorbitol, showing changes in the temperature dependence at the α and β glass-transitions, (b) BLS linewidths , neutron MSD , and 2 H-NMR spin-lattice relaxation data for ortho-terphenyl, and (c) neutron MSD , PS hole-fraction , o-PS lifetime , QELS , and 10 GHz dielectric loss data for PMMA, all showing similar behaviour. The DSC-determined values for T gα (black vertical lines) and the THz-TDS determined T gβ for sorbitol , DSC-determined T gβ for OTP , and the dielectric determined T gβ for PMMA (blue vertical lines), are shown. It should be noted that the identification of T gβ has been previously reported. The data are plotted with different vertical axes (not shown, see Supporting Information for individual plots).