QC 351 A7 no. 77 / Because of their light weight and low cost, transparent plastics would seem to be good materials for optical components. This thesis deals primarily with the feasibility of producing large ( >4 -in. -diam) plastic components of moderate precision (surface accuracies 1 fringe per inch of diameter). The structure and the physical and optical properties of plastics are discussed, with emphasis on their advantages and limitations for optical use. A series of experiments on grinding and polishing of plastics was conducted. Data are presented on grinding rates. Several polishing processes were evaluated, and a polishing technique for plastics was developed. Polishing rate data and surface roughness data are presented for several polishing processes. With proper techniques, we estimate that accuracies of about one fringe per inch are obtainable. A series of experiments was conducted on a process called compression forming, in which heat and pressure are applied to machined preforms in an attempt to obtain precision optical surfaces. The process is described in detail, and experimental results are discussed. Based on experimental results, improved processing conditions are suggested. Further experiments would be required to determine the ultimate process capability.