Abstract: A glassy thermotropic chiral nematic liquid crystalline composition comprises a glassy chiral nematic compound of low molar mass that includes a cycloaliphatic radical, a nematogenic moiety, and a chiral moiety, or a mixture of a nematic liquid crystalline compound of low molar mass that includes a cycloaliphatic radical and a nematogenic moiety and a chiral compound of low molar mass that includes a cycloaliphatic radical and a chiral moiety. Each cycloaliphatic radical contains 4 to about 18 carbon atoms. An optical device is formed from the described glassy thermotropic chiral nematic liquid crystalline composition.

Abstract: A thermotropic chiral nematic liquid crystalline copolymer composition comprises ##STR1## wherein --NEM-- and --NEM'-- are each independently nematogenic units of formula ##STR2## wherein R is H or CH.sub.3, --Q-- is an alkylene radical having 1 to about 8 carbon atoms,--X-- is --O--, --S--, or --CH.sub.2 --, --Y-- is ##STR3## --Z is --CN, --NO.sub.2 or --N.dbd.C.dbd.S, q and r are each independently 0 or 1;wherein --CHI-- is a chiral unit of formula ##STR4## wherein R is H or CH.sub.3, --Q'-- is an alkylene radical having 1 to about 8 carbon atoms,--X'-- is --O--, --S--, or --CH.sub.2 --,--Z' is an alkoxy, aralkoxy, alkylamino, or aralkylamino radical having 4 to about 12 carbon atoms and containing at least one asymmetric carbon atom,q' and r' are each independently 0 or 1;and wherein x is the mole fraction of chiral units and (y+y') is the total mole fraction of nematogenic units in said copolymer composition, and the ratio of x to (y+y') is from about 1:50 to 1:1.