Fluctuation-Dissipation-Theorem violation during the formation of a colloidal-glass

The relationship between the conductivity and the polarization noise is measured in a gel as a function of frequency in the range $1Hz - 40Hz$. It is found that at the beginning of the transition from a fluid like sol to a solid like gel the fluctuation dissipation theorem is strongly violated. The amplitude and the persistence time of this violation are decreasing functions of frequency. At the lowest frequencies of the measuring range it persists for times which are about 5% of the time needed to form the gel. This phenomenology is quite close to the recent theoretical predictions done for the violation of the fluctuation dissipation theorem in glassy systems.