Temperature dependence of the Raman spectra of amorphous glucose in the glassy and supercooled liquid states

Abstract

The Raman spectra of amorphous glucose between 300 and 4000 cm−1 over the temperature range 15–55 °C are reported. The spectra were recorded at several temperatures both below and above the glass transition temperature, Tg. A two‐dimensional covariance spectrum was computed and a least‐squares analysis was used to quantify the temperature dependences observed in the spectra. Several vibrational bands were found to be sensitive to the temperature of the material. Some bands also show a changing temperature dependence around the glass transition. A Fermi‐type function was found to be suitable as an empirical phenomenological model for the observed changes in the spectra. The wavenumber shifts and intensity changes observed in the spectrum were related to the intramolecular vibrations by a normal coordinate analysis of a single glucose molecule. The spectral changes in the ν(O–H) stretching region suggest a weakening of the hydrogen bond network at the glass transition. Other observed spectral changes suggest a weakening of the van der Waals interactions with increasing temperature, but these changes seem not to be related to the glass transition. Copyright © 2000 John Wiley & Sons, Ltd.

Making monosaccharide and disaccharide sugar glasses by using microwave oven

“…As we mentioned previously, a caramel has a very high molecular weight and a different chemical structure. Therefore, we can expect that the number of available Raman mode in caramel is much larger than those in the glass [11].…”

Hydration and temperature interdependence of protein picosecond dynamics

“…In a study of how internal molecular motions change with the temperature of a glassy solvent, So¨derholm and coworkers found intramolecular vibrational modes of glucose increase in intensity as the temperature increases through the glass transition temperature, in contrast to a harmonic solid, where the intensity decreases with increasing temperature. 29 The increase in intensity of these modes was associated with the softening of the intermolecular potential with the glass transition. One may expect a similar intensity dependence for the large scale structural vibrations of a hydrated protein as the surrounding solvent becomes more mobile.…”

Advances in two-dimensional correlation spectroscopy

“…Elucidation of the unfolding pathways was possible from the information on the sequence of events provided by the 2D VCD result. Söderholm et al [147] carried out the 2D Raman study of anhydrous amorphous glucose with a temperature scan around the glass-to-rubber transition temperature of 31 8C. Only synchronous (covariance) map was used in this study.…”