The review outlines the photophysical properties that a compound shoul
d possess if it is to be of value as a reagent for fluorescence micros
copy. Applications of fluorescence microscopy and related techniques t
o the study of the uptake of dyes by fibres, the photodegradation of d
yes and polymers (e.g. wool and lignin) and for determining the soften
ing temperatures of polymers are described.