Abstract: To provide a novel porous plastic optical transmission article which is easy to produce and excellent in heat resistance, flame retardancy, chemical resistance and solvent resistance and exhibits a low attenuation and a high bandwidth, and a process for its production. A porous plastic optical transmission article which is an optical transmission article made of an amorphous fluoropolymer containing substantially no C—H bond and which has a plurality of pores at least in a hollow tubular portion provided so as to surround the axial core portion of the optical transmission article. For example, an optical fiber, etc.

Abstract: There are provided a method of and an apparatus for producing ultrafine metal compound particles. An electrolytic bath having an anode and a cathode is partitioned into chambers by at least one ion exchange layer. An electrolytic solution containing metal ions as a starting material for the ultrafine metal compound particles is contained in a chamber on the anodic side of one ion exchange layer, and an alkaline electrolytic solution is contained in a chamber on the cathodic side of the ion exchange layer. When a voltage is applied between the anode and the cathode, the metal ions transfer from the anodic side chamber to the cathodic side chamber through the ion exchange layer, whereby ultrafine metal compound particles are precipitated in the alkaline electrolytic solution in the cathodic side chamber.

Abstract: A polarizing film comprising a uniaxially stretched film containing a polyvinyl alcohol having a degree of polymerization of at least about 2,500, and at least one polarizing agent selected from iodine and a dichroic dye, as well as a process for the production of the same. This polarizing film is superior in heat resistance and moist heat resistance to conventional films and has excellent optical properties, such as a high polarizing coefficient and transmittance.