Bismuth trioxide-tellurium dioxide glasses have improved infrared transmission characteristics

Ulrich, D. R.

English

NASA Technical Reports Server

June 1965	 Brief 65-10190 
NASA TECH	
A 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
IR-Transmission Glasses Formed from Oxides of Bismuth and Tellurium 
The problem: Development of bismuth trioxide 
(Bi203)—tellurium dioxide (Te02) glasses with im-
proved IR (infrared) transmission characteristics. 
Although glass compositions in this binary system 
are expected to have semiconducting characteristics 
and good IR transmission, little data on this system 
has been reported in the literature. Presently available 
IR-transmitting glasses have a cutoff wavelength of 
only 4.5 microns. 
The solution: Glasses formed from melts of 
Bi203 and Te02 containing from 75% to 90% (by 
weight) of Te02. 
How it's done: Mixtures containing different pro-
portions of the chemically pure components were 
melted in an electric furnace. The melts were then cast 
in preheated graphite molds and annealed at 250°C. 
Samples of the castings were then subjected to X-ray 
and electron diffraction analysis to identify those 
which had been converted to glasses. It was found that 
mixtures containing approximately 75% to 90% 
Te02 had the characteristics of a glass; samples con-
taining other proportions of Bi203 and Te02 were 
crystallized. All the glasses were opaque to visible light 
and crystallized at 550°C. Their resistivities were 
found to lie between those of good insulators and 
semiconductors.
The electrical resistivities and dielectric constants of 
two of the glass compositions at different tempera-
tures are listed below. 
COMPOSITION 
Te02
 81203
 TEMPERATURE	 RESISTIVITY	 DIELECTRIC (wt %I	 (°C)	 (ohm-cm)	 CONSTANT 
75	 25	 —196 3.6x 10 11 23.9 
27 3.3 x 10 10 25.8 
90	 10	 —196 2.6x1011 21.7 
27 5.7 X 10 10 26.1 
127 4.7x109
The glass containing 90% Te02 had an IR trans-
mission of 80% at 4 microns (upper transmission limit 
of present glasses), and a cutoff at approximately 7.5 
microns. 
Note: Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama, 35812 
Reference: B65-10190 
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about ob-
taining rights for its commercial use may be made to 
NASA, Code AGP, Washington, D.C., 20546. 
Source: D. R. Ulrich 
(M -FS-279) 
Brief 65-10190	 Category No. 03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern. 
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document. 
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IR-transmission glasses formed from oxides of bismuth and tellurium

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