Determination of Latent Transition Temperatures of Nonmesomorphs by Extrapolation Method in Binary Systems

Abstract

Eight binary systems consisting of mesomorphs and nonmesomorphs (A1 or A2, + B1, B2, … B7, B8) were studied with a view to determine the latent transition temperature (LTT) for the nonmesomorphic component (B) of a binary system by an extrapolation method. Encouraging results supporting earlier views and LTT values were obtained for seven binary systems. Instead of reporting a single value of LTT, the range of temperature or two or three values are reported herewith depending upon the possible paths of extrapolation. LTT reported earlier for nonmesomorphs lie within the range of temperature determined presently. Though the “group slope value” differs from the earlier reported value, the group efficiency order remains the same. Thus, the present investigation raises the credibility of an extrapolation method to determine LTT and group efficiency order for nematic mesophase. Component A1 and A2 are nematogenic, namely, p-(p′-n-propyloxy benzoyloxy) anisole (A1) (90.0 to 116.0) and p-(p′-n-butyloxy benzoyloxy) anisole (A2) (116.0 to 105.5). B1 to B8 are Schiff's bases. Transition and melting temperatures are observed through hot stage polarizing microscope for binary mixtures and pure components.