Search results for "Polarizing microscopy"
showing 2 items of 2 documents
4,4′‐Distyrylazobenzol als Mesogen
1992
4,4′-Distyrylazobenzene as Mesogen From 3,4-dihydroxybenzaldehyde (1) the tetraalkoxy-substituted 4,4′-distyrylazobenzenes (E,E,E)-5a – c are synthesized. A similar reaction sequence leads from ethyl 3,4,5-trihydroxy-benzoate (6) to the hexaalkoxy-substituted 4,4′-distyrylazobenzenes (E,E,E)-11 b, c. With the exception of 5a all products show thermotropic LC properties. Smectic phases have been characterized by polarizing microscopy and by differential scanning calorimetry.
Mesophase behaviour of 2,5-dibenzoyloxy-p-benzoquinone derivatives and tetrahydrobenzene tetraesters
1991
Abstract The synthesis of 2,5-dibenzoyloxy-p-benzoquinone derivatives, their products after reduction and tetraesters from tetrahydroxybenzene prepared from those products is described. Their phase behaviour was investigated by differential scanning calorimetry and polarizing microscopy and is discussed in terms of their detailed structure.