Abstract: A method for monitoring a property of a polymeric mass such as a coating or film comprising the steps of adding a fluorescence probe compound capable of fluorescing to a polymeric composition which has the ability to undergo changes in microviscosity, the ratio of the intensity of the fluorescence emission of said compound at two wavelengths changing in response to said changes in said microviscosity of said composition; curing said composition; causing said compound to fluoresce; measuring the fluorescence of said compound; calculating the ratio of the intensities of fluorescence emission of said compound at two or more wavelengths; relating said ratio to the monitored property of said composition.

Abstract: A method of writing and reading or writing, reading and erasing information in an optical recording medium is provided in which in an optical recording medium an optically active compound which is an inherently chiral dissymmetric olefinic chromophore is subjected to the action of circularly polarized light or is caused to undergo cis-trans isomerization during writing, is subjected to linearly polarized light during reading, and is subjected to linearly or circularly polarized light or light of a wavelength suitable to effect cis-trans isomerization for erasing.

Abstract: An optical recording medium and a method of writing, reading and erasing information in an optical recording medium are provided in which the optical recording medium comprises a carrier and a recording layer which contains at least one optically active organic compound, wherein said optically active organic compound is an inherently chiral dissymmetric olefinic chromophore.