Protectants which are cell membrane permeable, such as glycerol, have been used effectively in the cryopreservation field for a number of decades, for both slow cooling and vitrification applications. In the latter case the glass transition temperature (T_g) of the vitrification composition is key to its application, dictating the ultimate storage conditions. It has been observed that the addition of some electrolytes to glycerol, such as MgCl2, could elevate the T_g of the mixture, thus potentially providing more storage condition flexibility. The microscopic mechanisms that give rise to the T_g-enhancing behavior of these electrolytes are not yet well understood. The current study focuses on molecular dynamics simulation of glycerol mixed with a variety of metal chlorides (i.e., NaCl, KCl, MgCl2 and CaCl2), covering a temperature range that spans both the liquid and glassy states. The characteristics of the ion-dipole interactions between metal cations and hydroxyl groups of glycerol were analyzed. The interruption of the original hydrogen-bonding network among glycerol molecules by the addition of ions was also investigated in the context of hydrogen-bonding quantity and lifetime. Divalent metal cations were found to significantly increase the T_g by strengthening the interacting network in the electrolyte/glycerol mixture via strong cation-dipole attractions. In contrast, monovalent cations increased the T_g insignificantly, as the cation-dipole attraction was only slightly stronger than the original hydrogen-bonding network amongst glycerol molecules. The precursor of crystallization of NaCl and KCl was also observed in these compositions, potentially contributing to weak T_g-enhancing ability. The T_g-enhancing mechanisms elucidated in this study suggest a structure-enhancing role for divalent ions that could be of benefit in the design of protective formulations for biopreservation purposes.