Striae-free chalcogenide glasses

Patent metadata

Field	Value
Publication number	US-9708210-B2
Application number	US-201514712338-A
Country	US
Kind code	B2
Filing date	May 14, 2015
Priority date	Jun 3, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A method to synthesize striae-free chalcogenide glass using melt processing. A striae-free chalcogenide glass with uniform refractive index.

First claim

What we claim is:

1. A method to synthesize striae-free chalcogenide glass using melt processing, comprising the steps of:
melting chalcogenide glass inside a sealed silica ampoule;
providing a 2-zone furnace comprising an upper zone and a lower zone wherein the upper zone is at a higher temperature than the lower zone and wherein the zones are independently controllable temperature zones;
mixing by rocking the sealed silica ampoule inside the 2-zone furnace;
placing the sealed silica ampoule in a vertical position;
forming a glass melt as the upper zone is at a higher temperature than the lower zone;
positioning the glass melt such that the glass melt is within the lower zone; and
cooling slowly and quenching the temperature;
reducing the temperature of the upper zone at a rate of 0.6° C./min to 370° C.;
reducing the temperatures of the lower zone at a rate of 0.6° C./min to 260° C.;
holding these temperatures for 12 hours; and thereby
forming the striae-free chalcogenide glass.

2. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the step of preventing convection currents within the glass melt as the glass melt solidifies forming the chalcogenide glass.

3. The method to synthesize striae-free chalcogenide glass using melt processing of claim 2 , further comprising the step of preventing condensation of glass on the ampoule as the glass melt cools.

4. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the steps of:
allowing for an initial melting of the chalcogenide glass prior to the step of mixing by rocking; and
allowing for homogenization of the chalcogenide glass.

5. The method to synthesize striae-free chalcogenide glass using melt processing of claim 4 , further comprising the step of avoiding abrasion of the ampoule during the rocking step.

6. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the steps of:
maintaining the temperature of the lower zone at a temperature of about 700° C. for about 24 hours; and
maintaining the temperature of the upper zone at a temperature of about 100° C. greater than the temperature of the lower zone for about 24 hours.

7. A method to synthesize striae-free chalcogenide glass using melt processing, comprising the steps of:
loading arsenic and sulfur precursors sufficient to constitute a 120 gram batch of glass with the composition of 39% at. arsenic (As) and 61% at. sulphur (S) or about 71.88 grams As and 48.12 grams S into a silica ampoule under an inert gas atmosphere;
connecting the ampoule to a vacuum pump;
evacuating the ampoule for 4 hours at 1×10 −5 Torr;
sealing the ampoule;
placing the ampoule inside a rocking furnace with a ±45° angle of inclination wherein the furnace has a top zone and a bottom zone and wherein the zones are independently controllable temperature zones;
heating and rocking the ampoule;
heating the top zone and the bottom zone of the furnace at a rate of 3° C./min from room temperature;
heating the top zone to 850° C.;
heating the bottom zone to 750° C.;
holding constant the temperature of the top zone (850° C.) and bottom zone (750° C.) for 10 hours;
rocking the furnace at an inclination angle of ±45° to facilitate mixing and homogenization of the elemental components;
stopping the furnace motion;
setting the furnace to a vertical position or 90° fixed angle;
decreasing the temperature of the top zone at a rate of 1° C./min to 800° C.;
decreasing the temperature of the bottom zone at a rate of 1° C./min to 700° C.;
holding the furnace position and temperature profile for 24 hours to facilitate fining and settling of the glass melt;
reducing the temperature of the top zone at a rate of 0.6° C./min to 370° C.;
reducing the temperatures of the bottom zone at a rate of 0.6° C./min to 260° C.;
holding these temperatures for 12 hours;
forming a chalcogenide glass;
removing the ampoule from the furnace;
submerging the ampoule in a room temperature water bath for 10 seconds to quench the chalcogenide glass;
annealing the chalcogenide glass by placing the ampoule in another furnace at 180° C. for 10 hours; and
forming a striae-free chalcogenide glass.

Assignees

• Nguyen Vinh Q
• Kotov Mikhail
• Gibson Daniel J
• Bayya Shyam S
• Sanghera Jasbinder S
• Us Navy

Inventors

• Nguyen Vinh Q
• Kotov Mikhail
• Gibson Daniel J
• Bayya Shyam S
• Sanghera Jasbinder S

Classifications

• C03B5/06

  in pot furnaces {(C03B5/02 takes precedence)} · CPC title

• C03B5/16

  Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces · CPC title

• C03C3/321 Primary

  Chalcogenide glasses, e.g. containing S, Se, Te · CPC title

• C03B2201/86

  Chalcogenide glasses, i.e. S, Se or Te glasses · CPC title