We have succeed in preparing polar alignment in carbazole polymer films without an electric field. In this paper, we report a spontaneous polar alignment film prepared by a spin coating technique (spin-coated film). Orientation of chromophores in the medium and its stability were determined by second-harmonic generation (SHG) measurements and phase measurements of SHO. In general, polar alignments achieved in the electric filed have limitations on molecular structures, and they are thermodynamically and temporally unstable. However, the polar alignment in the spin-coated film are stable after annealing even at an elevated temperature above glass transition temperature. It is important to investigate molecular orientation in the medium in order to explore the mechanism of spontaneous polar alignment and improve its performance. We suggest a model of polar alignment in the spin-coated carbazole polymer film as the first step toward investigation of the mechanism.
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