Elastic incoherent neutron scatterings wavevector and thermal analysis on glass-forming homologous disaccharides

A wavelet analysis of Elastic Incoherent Neutron Scattering (EINS) intensity data collected, as a function of wavevector, on three glass forming systems, i.e. on the homologous disaccharides trehalose, maltose and sucrose, is presented. The wavelet transform allows to explore the wavevector behavior of the scattered intensity at different scales highlighting the correlation between the signal and the set of the scaled and translated mother functions. The analysis performed in the wavevector range of Q = 0.28 Å− 1 ÷ 4.28Å− 1 reveals the existence of different kinds of protons dynamics which cover different spatial scales. It emerges that, differently from previous analyses, for trehalose the intensity data at all the investigated temperature values are constantly lower and sharper in respect to those of maltose and sucrose, giving rise to a global spectral density along the wavevector range markedly less extended. Furthermore, the application of an interpretative model for the partial and global EINS intensity temperature behavior allows to put into evidence both the different wavevector dependence of the system relaxation times, extracted from the intensity vs. temperature inflection point, and the higher thermal restrain of trehalose in respect to the other two homologous disaccharides.