A synthetically novel and flexible side-chain liquid crystalline (SCLC) azobenzene polyester architecture intended for reversible optical storage has recently been introduced. The modular design allows four structural parameters to be individually modified. Polyesters with molecular masses up to 100,000 have been obtained by melt transesterification of the selected precursors. The influence and importance of the four structural parameters: the 1) methylene main-chain and 2) methylene side-chain spacer length, 3) the substituent on azobenzene, and 4) the polyester molecular mass, for the reversible optical storage are discussed. Prominent optical storage features are the unnecessary prealignment of SCLC polyester films prior to the writing process, and sensitivity in a broad wavelength window (415-532 nm). Information can be recorded either through polarization holography or direct computer generated pattern (grey tones). Polarization holography has resulted in high diffraction efficiency (> 50%) and high storage density (> 5000 lines/mm interference gratings) lasting presently well over 4 years without any sign of fatigue. Non-destructive read out is performed with red light (600-750 nm). Erasing the information can be achieved by heating the polyester film to 80°C or irradiating it briefly with UV-light. In the latter case at least 10,000 write, read and erase cycles are possible. Atomic force and scanning near-field optical microscopic investigations of gratings prepared with orthogonally polarized overlapping beams have demonstrated polarization preservation despite extensive mass transport and surface corrugation in the SCLC polyester film after the irradiation process. Polarization Fourier-Transform infrared studies of laser induced segmental motion in selectively deuterated SCLC cyanoazobenzene polyesters have revealed that not only the azobenzene chromophores but also main-chain and side-chain spacers align preferentially perpendicular to laser polarization.