Devitrification of the glassy state in suspensions of charged platelets

Colloidal suspensions of charged gibbsite platelets at salt concentrations of 10(-2) M and below and with a sufficiently high particle concentration form a kinetically arrested, glassy state. We study the evolution of the glassy state in suspensions of three different gibbsite systems. Despite differences in size and polydispersity, we observe small, iridescent grains of the hexagonal columnar phase, for all these systems after periods of months to years. The connections between this devitrification phenomenon and the structure of the glassy state are discussed.