''para''-Azoxyanisole (PAA) is an organic,

aromatic compound Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past grouping ...

. In a solid state, it appears as a white

powder A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms ''powder'' and '' granular'' are sometimes used to disti ...

, but when heated it forms a liquid crystal. As one of the first known and most readily prepared liquid crystals, PAA has played an important role in the development of liquid crystal displays.''Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry'', Joseph A. Castellano, Its liquid crystal range is from 118 °C to 136 °C. The solid to

nematic Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way. The ...

transition is at 118 °C and the nematic to

isotropic Isotropy is uniformity in all orientations; it is derived . Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix ' or ', hence ''anisotropy''. ''Anisotropy'' is also used to describe ...

liquid transition at 136 °C.

References

{{DEFAULTSORT:Azoxyanisole, Para- Azo compounds Amine oxides Liquid crystals Phenol ethers