  While various structural and dynamical precursors to vitrification have been
identified, a predictive and quantitative description of how subtle changes at
the microscopic scale give rise to the steep growth in macroscopic viscosity is
missing. It was proposed that the presence of long-lived bonded structures
within the liquid may provide this connection. Here we directly observe and
quantify the connectivity dynamics in liquids of charged colloids en-route to
vitrification. Based on these data, we extend Dyre's elastic model for the
glass transition to account for particle-level dynamics; this results in a
parameter-free expression for the slowing down of relaxations in the liquid
that is in quantitative agreement with our experiments.
