Characteristic length of glass transition from calorimetry for benzoin isobutylether in a series of nanometer pores

Abstract

Temperature modulated dynamic scanning calorimetry (TMDSC) yields the characteristic length or, correspondingly, the cooperativity of dynamic glass transition of a molecular liquid in nanometer size pores. The TMDSC traces for benzoin isobutylether are not disturbed by structuring effects that are usually observed in standard DSC. The bulk length of about ξ α = 3 nm decreases with decreasing pore diameter below D = 12 nm, down to ξ α = 1.6 nm in D = 2 nm pores. The glass transition temperature decreases concomitantly. This can be understood in the framework of the hindered glass transition.