Terahertz spectra for several amorphous materials over a range of temperatures, from below to above the glass transition: Figure 2 (fig2_data.csv): Absorption coefficient and refractive index of polyvinylpyrrolidone/vinyl acetate at 1 THz prepared as tablet and thin film from melt. Figure 5 (fig5_data.csv): Terahertz absorption of amorphous sorbitol, trehalose and BSA between 80 - 340 K at 0.8 THz. Figure 6 (fig6_data_THz-TDS.csv): Dielectric losses of amorphous sorbitol observed by terahertz spectroscopy. Figure 6 (fig6_data_synchrotron.csv): Dielectric losses of amorphous sorbitol observed at Diamond synchrotron facility. Figure 7a (fig7a_data.csv): Rescaled absorption coefficient of amorphous sorbitol between 80 - 420 K measured by terahertz spectroscopy Figure 7b (fig7b_data.csv): Refractive index of amorphous sorbitol between 80-420 K measured by terahertz spectroscopy.