CORRELATION INDEX (T-G-ALPHA - T-G-BETA)/T-G-ALPHA AND ACTIVATION-ENERGY RATIO DELTA-EPSILON(A-ALPHA)/DELTA-EPSILON(A-BETA) AS PARAMETERS CHARACTERIZING THE STRUCTURE OF LIQUID AND GLASS

The beta-relaxation process was calorimetrically observed in o-terphenyl. It was indicated to be elementary for the alpha-process, and a ''correlation index'' c{=(T-g alpha - T-g beta)/T-g alpha} and an activation energy ratio R{=Delta epsilon a alpha(T)/Delta epsilon a beta} were proposed as parameters characterizing the structure of liquid and glass. The increase in the size of the correlated region of molecules at low temperatures was well represented by the increase in the ratio R. Some universal relation was discussed to potentially hold between the c-index and the fragility m such that m = 120 c + 17 in c < 0.6 with taking the pre-exponential factor of relaxation times tau(0) = 10(-14) s.