2.6. Microstructure
The crystal morphology was evaluated using polarized light
microscopy coupled to a digital video camera .
The samples were previously melted at
100 C in an oven and with the aid of a capillary tube, a drop was
placed over a pre-heated glass slide and covered with a
coverslip.
The slides were kept in an incubator maintained at the
temperature of 25 C for 4 h and then placed on the microscope hot
stage, also held at
25 C.
The images were captured by the applicative Image Pro-Plus
version 7.0, using polarized
light under a magnification of 40 times, and previous calibration of
the microscope using slide micrometric.
Within each
slide, three visual fields were arbitrarily chosen and focused.
The
mean diameter of the crystals was selected as the quantitative
parameter and calculated using the software Image Pro-Plus
version 7.0