NONADIABATIC SCANNING CALORIMETER

A high-resolution computerized calorimeter capable of fully automatic operation in either ac or relaxation modes is described. Emphasis is g iven to a new version of the relaxation technique in which the heater power is ramped linearly in time. This improvement results in superior performance and convenience in studying both first-and second-order p hase transitions and allows quantitative evaluation of latent heats as well as pretransitional heat capacity variations. Examples are given for the use of this calorimeter in the study of liquid crystal phase t ransitions. (C) 1998 American Institute of-Physics.