Fig. 1: Optical Kerr-effect (OKE) spectra of supercooled and vitrified tetrabutyl orthosilicate (TBOS).
From: Understanding the emergence of the boson peak in molecular glasses
a All data from 90 to 440 K. b, c Two representative temperatures and fits. The black line in (b) is the component due to diffusive α relaxation fitted to a Havriliak–Negami function, which freezes out below the glass transition and is therefore absent in (c). The two green bands at low frequency are intermolecular modes fitted to two Gaussian functions. The blue band is an intramolecular vibration fitted to a Brownian oscillator function with constant amplitude. The yellow curves are additional intramolecular vibrations. d Temperature-dependent amplitudes of the low-frequency (AG1, red disks) and high-frequency (AG2, blue squares) intermolecular modes. The lines are guides to the eye. While these amplitudes change, the amplitude of the higher frequency intramolecular modes remain unchanged with temperature as expected.
