Abstract
The melting points, glass transitions and enthalpies of fusion of crystalline hydrates in binary water-raffinose mixtures have been studied by differential scanning calorimetry (DSC) over the accessible composition range. X-Ray diffraction was used to identify the crystalline forms. From the liquidus and solidus curves and shapes of the DSC scans, a raffinose trihydrate has been identified, and lower hydrates are also believed to exist. In the phase coexistence curve at higher raffinose concentrations a minimum point is observed, which is thought to be the eutectic of trihydrate and a lower hydrate. The glass-transition profile for the binary system has been measured over the experimentally accessible composition range and the data fitted to the Gordon-Taylor equation, from which the glass-transition temperature for anhydrous raffinose is obtained as 376.4 K.