A new four-step synthetic-route for combining azochromophores with melamine
resins was developed and their potential for E/Z-isomerization were shown
by Kelvin-probe technique. Despite of other melamine resins, the basis mole
cule of the synthesized melamine-chromophore and the resulting melamine-chr
omophore resins is the 2,4,6-trichloro-1,3,5-triazine, the cyanuric chlorid
e. In the first step, the azochromophore was bonded to the s-triazine-ring.
Then, the residual chlorines of this triazine-chromophore were substituted
by ammonia or primary amines. In the third step, formaldehyde was added, l
eading to melamine-chromophore monomers. For increasing the stability and t
he solubility of these monomers the reactive methylolgroups were etherifica
ted with methyl or butyl alcohol. The result of these systems is a crosslin
kable melamine-chromophore monomer which is converted in a resin by thermal
treating or by acids. An optically induced switching of two different mela
mine-chromophore monomers and the resins were monitored by measuring the su
rface, potential. It was done by Kelvin-probe technique. The results show a
high surface potential difference between the cis- and the trans-state of
the ate-group-systems, depending first on the attached chromophore and seco
nd whether the prepared films are monomer-layers or resins. (C) 1999 Elsevi
er Science S.A. All rights reserved.