Thermotropic systems with fixed domains (TSFD) consist of a thermotropic additive dispersed in the matrix of a UV curable resin. The additive serves as scattering domain, thus causing the TSFD to change its light transmittance from highly transparent to opaque upon reaching a certain threshold temperature (i.e. the melting temperature of the additive) reversibly. Potential applications of TSFD layers are overheating protection glazings for solar thermal systems. The overheating protection performance is determined by the layer morphology, i.e. scattering domain size and distribution. Thus, the overall objective of this master thesis was to perform a comprehensive characterization of TSFD morphology also upon heating and cooling applying Atomic Force Microscopy (AFM). Specific focus was given to the effect of additive type on the formation of scattering domains. Furthermore nanomechanical characteristics were determined by means of Force/Distance spectrometry. The TSFD formulated with the additive type exhibiting a short chain length and thus low molecular weight displayed roughly spherical scattering particles with dimensions between 0.6 to 4 micrometers, consisting of primary particles with dimensions between 25 to 500 nanometers. Stiffness values of 0.45 to 0.85 N/m and 6.17 to 9.52 N/m were determined for the scattering domains and the matrix, respectively. The scattering domains showed a uniform distribution across the film thickness. Upon heating, melting and deliquescence of the additive along with migration was ascertained. After cooling to ambient temperature the formation and growth of terrace-like additive domains on the surface was recorded. Force/Distance spectrometry yielded a 5 to 10 nanometers thick additive layer which coated wide areas of the sample surface after the heating cycle. The additive type with long-chain molecules and hence high molecular weight developed anisotropic scattering domains resembling distorted disks without predominant orientation in the TSFD investigated. The domains exhibited a diameter up to 50 micrometers and a thickness between 200 and 600 nanometers. Stiffness values of 0.48 to 1.61 N/m and 7.13 to 20.76 N/m were recorded for the scattering domains and the matrix, respectively. Upon heating, swelling and deliquescence of the additive were detected. After cooling to ambient temperature a partial recovery of swelling was observed. Again, Force/Distance spectrometry yielded a 5 to 10 nanometers thick additive layer which coated small areas of the sample surface after the heating cycle. Due to the observed additive domain dimensions, TSFD formulated with high molecular weight additive exhibits slightly better light-shielding properties.