Mono-, bi-, and multimorphs are poled electrets with +/0, +/-, and more complicated alternating-polarity dipole-orientation patterns, respectively. Because of their unusual macroscopic piezo- and pyroelectrical as well as nonlinear optical properties, such structures are of particular interest for special transducer and optical waveguide applications. In this contribution, the preparation of such dipole-polarization patterns in ferroelectric and amorphous polymer electrets and their nondestructive probing by means of thermal and acoustical techniques are reviewed.