CALORIMETRIC STUDY OF HEPTYLOXYBENZYLIDENE BUTYLANILINE IN SILICA AEROGELS

A high resolution a.c. and relaxation calorimetric study has been carr ied out on heptyloxybenzylidene butylaniline (7O.4) in two silica aero gels with mass densities rho=0.08 and 0.17 g cm(-3). Bulk 7O.4 exhibit s strongly first order N-I, N-S-A and S-C-CrG transitions as well as a mean-field second order S-A-S-C transition. The 7O.4/aerogel samples exhibit three first order transitions (N-I, N-S-A, S-A-crystal) that a re appreciably shifted and broadened relative to bulk 7O.4. The S-A-S- C transition is not observed in either of the aerogel samples.