A model for the fragile-to-strong transition in water

A model based on the existence of two different competing local structures in water is described. It is shown that it can explain the transition between fragile and strong behavior that supercooled water has around 220 K. The high temperature behavior is similar to that observed in standard fragile glass-formers. The strong behavior at low temperatures is associated with the existence of a remanent configurational entropy coming from the possibility of locally choosing between the two possible environments.