Notably, to investigate the effects of the addition of mAb1 on the values of T g, and T g,↵ , we first studied a a stable model system, which is routinely used in protein formulations: an excipient mixture of sucrose/glycine . The sucrose/glycine hydrogen bonded network exhibits values of T g, = 220 K and T g,↵ = 303 K (Figure ), that are significantly higher than those observed for F5, F6, and F7 (Table ). This suggests that when mAb1 is added to a formulation it creates a more loosely bound hydrogen bonded network, with more free volume available and reduced T g, and T g,↵ values, compared to the more strongly bound hydrogen bonded network of sucrose and glycine. This further supports that the local and large-scale mobility of a system are sensitive to the strength of the hydrogen bonding network and the free volume effects.