as the static structure factor.'
author:
- 'Hervé M. Carruzzo$^{\dagger}$ and Clare C. Yu'
title: 'Structural Probe of a Glass Forming Liquid: Generalized Compressibility'
---

epsf

Introduction
============

The glass transition is still not well understood despite extensive study. There have been two main theoretical approaches to the problem: dynamic and thermodynamic. Theories in the first category view the glass transition as a kinetic phenomenon characterized by a growing relaxation time and viscosity [@Ediger96; @Fourkas97; @Gotze92; @Donati98; @Yamamoto97b]. When the relaxation time exceeds the measurement time, particle motion appears to be arrested resulting in the glass transition. One of the most prominent theories espousing this view is the mode coupling theory (MCT) in which ideally the relaxation time diverges at a temperature $T_{C}$ above the experimental glass transition temperature [@Gotze92]. Interesting and fruitful concepts such as dynamic inhomogeneities [@Donati98; @Yamamoto97a; @Tracht98] and the influence of the energy landscape on relaxation processes [@Goldstein69; @Sastry98] have resulted from this approach. The thermodynamic viewpoint attributes the glass transition to an underlying phase transition hidden from direct experimental observation by extremely long relaxation times [@Ediger96; @Fourkas97; @Adam65; @Gibbs58; @Mezard99]. In most scenarios there is an underlying second order phase transition associated with a growing 