United States of America As Represented by the Secretary of the Air Force

Government of the United States of America, As Represented by the Secretary of Commerce

Steven C Roth

Anthony J Bur

Charles L Thomas

Francis W Wang

Robert E Lowry

An optical sensor containing polarizing optical components measures fluorescence anisotropy of fluorescent dyes. The measurement involves the detection of vertical and horizontal components of fluorescent light. Using Glan-Taylor and Wollaston calcite polarizers, both vertical and horizontal components are collected by separate optical fibers and measured simultaneously using a two-channel photon counter. One application of this sensor is the measurement of molecular orientation during polymer processing. Two sensor head designs are described, one of which fits into the 1/2 inch instrumentation port in polymer processing machines. To carry out process monitoring, a fluorescent dye is mixed with a polymer resin at approximately 10 ppm by weight concentration. Dyes which have geometrical asymmetry in their molecular structure or are covalently bonded to the polymer molecule are usually used. The anisotropy measurement yields information about the orientation of the dye molecule in an oriented medium. Anisotropy measurements of fluorescent dyes in media other than polymers can also be obtained using this sensor.

Optical sensor for measuring fluorescence anisotropy during polymer

A method of measuring fluid properties of a polymer melt, undergoing shear and/or extensional flow which utilizes fluorescent anisotropy. The method utilizes a polymeric chromophore which includes a bifunctional anthracene that is covalently bonded to polybutadiene. The invention also involves an optical probe which is designed to be inserted into existing temperature and/or pressure probe ports in processing equipment. The probe includes a rotatable polarizer and emission collection fibers.

Optical sensor for the measurement of molecular orientation and

Accurate dynamic pressure data in a changing thermal environment is obtained through the use of a pressure gage formed from polyvinylidene fluoride (PVDF) polymer material. The temperature compensation pressure gage has three major elements: an active PVDF transducer which obtains remote pressure readings which are uncorrected for thermal effects; a thermocouple having a short rise time allowing an output thermal signal which dynamically responds to changing thermal conditions; and a compensation amplifier circuit receiving the uncorrected pressure readings and the dynamic thermal signal and producing an output signal representing accurate pressure data which is corrected for changing thermal conditions. Also disclosed are the details of making an active PVDF transducer.

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Frederick, MD, United States of America

Steven C Roth