Experimental Results and Problems Concerning “Blue Phases”

摘要: Most of the cholesteric mesophases formed by esters cholesterol exhibit selective reflection circularly polarized light in u. v. region at temperatures close below clearing point /1/. The well known colours visible either occur near phase transitions to smectic or so-called compensated mixtures However, cooling down only a few tenths Kelvin bright appear (mostly blue colours) which disappear on further /2/. As early as 1906 Lehmann /3/ noted that these belong an optically isotropic modification. In his opinion this modification represents stable distinct from ordinary one.