Quantitative investigation of the mean-field scenario for the structural glass transition from a schematic mode-coupling analysis of experimental data

摘要

A quantitative application to real supercooled liquids of the mean-fieldscenario for the glass transition ($T_g$) is proposed. This scenario, based onan analogy with spin-glass models, suggests a unified picture of themode-coupling dynamical singularity ($T_c$) and of the entropy crisis at theKauzmann temperature ($T_K$), with $T_c>T_g>T_K$. Fitting a simple set ofmode-coupling equations to experimental light-scattering spectra of two fragileliquids and deriving the equivalent spin-glass model, we can estimate not only$T_c$, but also the static transition temperature $T_s$ correspondingsupposedly to $T_K$. For the models and systems considered here, $T_s$ isalways found above $T_g$, in the fluid phase. A comparison with recenttheoretical calculations shows that this overestimation of the ability of aliquid to form a glass seems to be a generic feature of the mean-fieldapproach.