engleski

The EPR Study of Trehalose Frozen-in Disorder

Trehalose, a glass-forming disaccharide found in nature, exhibits the unusual bioprotective properties like anhydrobiosis or cryoprotection. These phenomena prompted the investigation of molecular dynamics in the wide range of trehalose preparations in the solid state. Due to the fact that trehalose exhibits the highest glass transition temperature, Tg, and the best-developed boson peak of saccharides, it is interesting to be studied in the context of low-temperature anomalies of glasses related to the impact of hydrogen-bonded network. Here we present the comparative study of trehalose glassy and anhydrous polycrystalline form, trehalose-β, using pulsed X-band electron paramagnetic resonance (EPR) spectroscopy. The radiation-induced paramagnetic centers are used to study the coupling of the electron spin with the lattice as a function of the frozen-in disorder. The effective spin-lattice relaxation time is presented in the large temperature interval, from 0.012 Tg to 0.7 Tg . The experimental data are indicative of a more effective energy exchange between the spin system and the lattice for the paramagnetic defects in the glassy than trehalose-β crystalline state. The theoretical analysis of the experimental data is put into the framework of the contribution of the disorder modes.

trehalose; relaxation; EPR

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