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CHEMISTRY LIBRARY

NBS CIRCULAR 569

5

Fused-Quartz Fibers

A Survey of Properties, Applications, and Production Methods

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PERIODICALS OF THE NATIONAL BUREAU OF STANDARDS

(Published monthly) The National Bureau of Standards is engaged in fundamental and applied research in physics, chemistry mathematics, and engineering Projects are conducted in fifteen fields: electricity and electronics, optic and metrology, heat and power, atomic and radiation physics, chemistry, mechanics, organic and fibrous materials, metallurgy, mineral products, building technology, applied mathematics, data processing systems, cryogenic engineering, radio propagation, and radio standards. The Bureau has custody of th national standards of measurement and conducts research leading to the improvement of scientific an engineering standards and of techniques and methods of measurement. Testing methods and instrumenti are developed; physical constants and properties of materials are determined; and technical processes art investigated.

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Summaries of current research at the National Bureau of Standards are published each month in the Technical News Bulletin. The articles are brief, with emphasis on the results of research, chosen on th: basis of their scientific or technologic importance. Lists of all Bureau publications during the preceding month are given, including Research Papers, Handbooks, Applied Mathematics Series, Building Mate. rials and Structures Reports, Miscellaneous Publications, and Circulars. Each issue contains 12 or mori two-column pages; illustrated. Annual subscription: domestic, $1.00; 35 cents additional for foreign mailing.

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UNITED STATES DEPARTMENT OF COMMERCE Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS A. V. Astin, Director

Fused-Quartz Fibers

A Survey of Properties, Applications, and Production Methods

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For sale by the Superintendent of Documents, V. S. Government Printing Office, Washington 25, D. C.

Price 25 cents

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U35 no. 569-575

FUSED-QUARTZ FIBERS

CHEMISTRY LIBRARY

A Survey of Properties, Applications, and Production Methods

Nancy J. Tighe

Fused-silica fibers have an important function in many measuring instruments used in scientific research. Much of the information on the production and fabrication methods and on the properties of the fibers is widely scattered throughout the technical literature. This Circular is a survey of this literature and a summary of the findings. A bibliography of pertinent references on the subject is included to provide the sources of more complete and detailed information necessary for specific applications.

1. INTRODUCTION

This Circular is the result of a literature survey covering the properties and the uses of fused-silica fibers. Silica fibers or, as they are frequently called, quartz fibers, have had wide application in precision measuring instruments despite the fact that the factors which affect their behavior are not fully known. The survey of the literature revealed that while some investigations are made in order to obtain specific values of particular properties, other studies are made primarily to develop more completely the theoretical treatment of glasses and their relation to liquids and solids. Although this Circular covers primarily those properties related to the actual use of the fibers, it mentions those theories and properties needed for better understanding of the variations observed in the testing and use of silica fibers. It is hoped that this summary will aid in the production of silica fibers having more reproducible and predictable properties.

Throughout the literature such terms as fused silica, fused quartz, vitreous silica, silica glass, quartz glass re used to refer to types of fused silica. The use or misuse

of the terms has been discussed frequently [7, 112, 301, 303 to 305) but little uniformity has resulted. The terms used are meant to indicate the degree of transparency or the source of the raw material. For instance, in the glass industry the term fused silica may refer to the transparent material formed by the fusion of quartz sand or other forms of silica, while the term fused quartz may refer to the transparent material formed by the fusion of pure quartz rock crystal. However, this designation of terms is not used consistently, for the material is frequently described as clear or translucent fused quartz or as clear or translucent fused silica. In this Circular the term fused silica will be used in general for that glass formed by the fusion of silica. Where necessary, this term is modified by the adjectives clear or translucent. For instance, where the condition of transparency is evident from the use, such as in fibers which are drawn from clear fused silica, the fibers are ferred to simply as silica fibers.

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Figures in brackets refer to the references listed in the bibliography.

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