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Optical fibers for distributive lighting systems must exhibit high transparency and accurate color rendition. These properties must also be maintained after extended use. The SAE Distributive Lighting Task Force is defining the mechanical, optical, and chemical durability specifications for exterior applications, the most demanding of which is forward lighting. We have developed methods to test the stability of plastic optical fibers to heat, to light, and to combinations of heat and light. When plastic optical fibers fail, it is due to a color temperature shift rather than to a loss in transparency. That is, the light that the fiber or light pipe transmits shows a noticeable color change before its intensity is diminished significantly. The goal is to minimize the color temperature shift from the high-intensity discharge (HID) light sources. Our durability test methods monitor these color changes of transmitted light.

LOW density, ease of fabrication, low thermal conductivity, available transparency, and low unit cost for mass-production items are characteristics of organic plastic materials that make them attractive to the designer and the engineer. Before full use of plastics can be made, however, it is necessary for both the designer and the engineer to have an extensive practical tabulation of their chemical and physical characteristics. Today's cut-and-try methods used with plastics must give way to theoretical design considerations. The authors of this paper have outlined those things that should be considered in every application with plastics, illustrating their point with pertinent data on the thermoplastic resin known as Plexiglas.

Temporary shear loss characteristics of multigraded engine oils were measured in a newly developed engine oil pump rig. Correlations of the results with high pressure capillary viscometry data indicate that the test apparatus generates shear rates in the range of 2-3 × 105 s-1. One advantage of this technique over similar mechanical approaches is that the test rig causes virtually no permanent shear degradation. Test results are reported for a variety of polymer types, and the relationship of permanent and temporary shear losses is discussed.

A new concept in unsaturated polyester resins now provides exceptionally smooth surfaces on molded glass fiber reinforced structures. The resins have good cure speed and contribute to excellent strength retention of molded parts at elevated temperatures. Premix compounds based on low shrink resin are well suited for injection molding because of an unusual combination of attributes. The use of these unique resins will offer reduced finishing costs for glass mat reinforced moldings and open new “appearance” applications for the versatile premix molding process.