Page "Liquid crystal" Paragraph 24

Thermotropic phases are those that occur in a certain temperature range.

If the temperature rise is too high, thermal motion will destroy the delicate cooperative ordering of the LC phase, pushing the material into a conventional isotropic liquid phase.

At too low temperature, most LC materials will form a conventional crystal.

Many thermotropic LCs exhibit a variety of phases as temperature is changed.

For instance, a particular type of LC molecule ( called mesogen ) may exhibit various smectic and nematic ( and finally isotropic ) phases as temperature is increased.

An example of a compound displaying thermotropic LC behavior is para-azoxyanisole.