Monitoring of a drying process in polymer water solutions by dynamic speckle detection

Observation of speed of processes by dynamic speckle analysis has been applied to different samples of industrial or biological nature. The method allows for indicating regions of lower or higher activity on the sample surface through statistical processing of the speckle patterns formed on this surface under laser illumination. The aim of the paper is to check applicability of dynamic speckle technique for detection of the drying process in polymer water solutions. For the purpose, we recorded several sets of 256 correlated in time speckle patterns of a transparent drop of PAZO water solution on a glass plate illuminated by a He-Ne laser. The sets were separated by intervals of 5 minutes, and the last set was recorded 75 minutes after the start of the experiment. For statistical description of activity on the observed sample we chose evaluation of a temporal structure function. The obtained two-dimensional maps of the structure function at different time lags demonstrated efficiency of dynamic speckle analysis for monitoring of drying processes in polymer water solutions.