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In this thesis we present some measurements of azimuthal anchoring energies for the nematic liquid crystal 5CB. The 5CB was in contact with glass surfaces covered with a thin polyimide substrate (Nissan corporation, SE-3510), that has been rubbed along a given direction. The glass surfaces were supplied by Stephane Joly of NEMOPTIC industry. Two different experimental methods -recently proposed by our group- have been used: a reflectometric method and a transmission method. Both these methods use a monocromatic laser beam (Laser He-Ne). In these subsrates we have measured a very high anchoring energy: Wa=3.5 10^(-4)J/m^2 (at T=25°C), corresponding to an extrapolation length de=12 nm.
We have studied how the anchoring energy depends from temperature and we descovered that it rapidly decreases near the clarification temperature. We have also observed the easy axis gliding, as the surfaces with weak anchoring energy.