A time-resolved ultramicroscope was developed to monitor the process of pul
se-laser-induced melting of 9,10-dicyanoanthracene microcrystals on poly(et
hyl methacrylate) films. The microscope can detect sub-micrometer particles
, but with an image (spacial) resolution of 2 mum and a time resolution of
400 ps. Quantitative comparison between images obtained at a certain time d
elay after an excitation laser pulse and a pre-irradiated image is achieved
using a correlation function. It was found that crystals having a size of
about 10 mum turn in hot liquid droplets within the nanosecond excitation p
ulse after which 80% of the droplets solidify with a time constant of 9 ns.
The residual 20% of hot liquid droplets appear to have either evaporated o
r fused and dispersed into the polymer with a time constant of 15 ns. (C) 2
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