Glass Chemical Strengthening with Science and Experience

If your glass product would benefit from dramatically increased fracture strength, fatigue resistance, thermal shock resistance, and/or abrasion resistence, you should take a careful look at chemically strengthened glass from Saxon Glass Technologies.
The glass experts at Saxon may be able to provide 50 to 800% increases in design strength - using your current glass compositions.

Process Overview

What occurs during chemical strengthening?

Large K+ ions exchange sites with host Na+ ions in glass forcing surface into compression and creating a closure stress on cracks, there by increasing the strength and making it more difficult for new cracks to form. Furthermore, the surface compression all but eliminates problems of "delayed failure"; i.e. time-dependent weakening under load, and increases abrasion resistance. The ion exchange process is carried out at temperatures below the glass transition temperature, i.e., while glass is still nearly solid.

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Ionex? is suitable for most glasses, typically used in pharmaceutical, container, and cover glass for electronic devices. Increase usable strength by 50% to 800% over untreated glass.


Like Ionex?, Ion-Klad? is also suitable for most glasses, but offers a deeper compression case-depth for greater forgiveness to handling-generated surface flaws.


A chemically strengthened glass for use in transparent armor laminates. Exhibiting a modulus of rupture of nearly 1 GPa (~144,000 psi), Ion-ArmorTM offers superior performance over typical soda-lime silicate glass.
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Process Design

Conceptually, chemical strengthening is a simple process. In practice, the process is influenced by a number of factors, and the results vary considerably. It is often difficult to determine whether a particular treatment has produced the desired effect. This is because a quantification of glass abrasion during product manufacture, as well as during subsequent application, is difficult. Strength as measured by the average modulus of rupture (MOR) is often used to assess the effectiveness of a particular treatment, but the results can be misleading. One cannot design an appropriate treatment based only on average MOR, and while average MOR is useful as a?quality control test, it must be used with caution and only in conjunction with other measurements,?such as those which provide an indication of:
  • The depth of the compression layer - i.e. what is the case depth?
  • The magnitude of the surface compression stress.
  • A statistically meaningful description of the distribution of MOR values.
  • Some measure of the sensitivity of the strengthened glass to handling/abrasion/impact.

Figure 2-update

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About Us

Saxon Glass Technologies, Inc. was started in 1996 when a large glass maker came to the New York State College of Ceramics at Alfred University in search of a solution to their glass strength problems. After the successful demonstration of trial runs, a shop was?set up at the Ceramic Corridor Innovation Center to meet the new challenge from the New York State legislature to help with the economic growth of the region. Dr. Arun Varshneya, president and CEO of the company, is an educator-cum-entrepreneur who has over 45 years' experience in research on ion exchange strengthening, and has authored several key publications and patents dealing with the process. The company has grown in several areas where strengthened?glass provides a more reliable and safe approach to product application. The scientific and engineering staff at Saxon understands the technical issues in producing consistent high-strength glasses and have developed processes for "optimized" ion exchange through which the time and cost of strengthening can be significantly reduced.

Dr. Arun K. Varshneya, emeritus professor of glass science and engineering, serves as the president.

News, Awards, Distinctions, and Presentations

Recent News:

Nathan Card presents “Design and testing of a large sub-hemispherical glass port for a deep-sea CAMERA” at the 20th University Conference on Glass, Penn State University August 13, 2018.

  • Co-authored with Francois Cazenave of the Monterey Bay Aquarium Research Institute, Moss Landing CA, Eric H. Baker of the Connecticut Research Technologies, Gates Mills OH, George D. Quinn of the National Institute of Standards and Technology, Gaithersburg MD, Paul Remijan of Fathom Imaging Inc., Brimfield MA, Jonathan D. Salem of NASA Glenn Research Center, Cleveland OH and Dr. Varshneya, this paper presented (link) how a highly specialized team tackled various aspects of a large glass dome for a camera port in an autonomous vehicle to explore ocean depths as much as 1500 m.
  • Glass dome was chemically strengthened at Saxon Glass to a surface compression magnitude of ~430 MPa and a depth of layer of 45 microns which overcame hydrostatic pressure with a fracture probability less than 10-8 ppm under a proof test pressure corresponding to ~2,100 m depth sustained for 200 h. The chemically strengthened glass dome was actually able to withstand a depth of 5,000 m! According to Cazenave, the autonomous vehicle equipped with the strengthened dome is in use routinely.
  • PDF of the 2018 MBARI-Penn State University presentation

Dr. Varshneya receives the most coveted 2018 George W. Morey Award of the American Ceramic Society, Glass & Optical Materials Division at the GOMD meeting, San Antonio TX, May 22nd, 2018.

  • His presentation was entitled, “Chemically Strengthened Glass: Science, Technology and Its Future”. Dr. Varshneya gave a comprehensive update on the science and technology of chemically strengthened glass particularly elaborating the potential applications.
  • PDF abstract of the presentation
  • PDF of the 2018 Morey Lecture

At its Board of Fellows meeting March 21st, 2018, the UK Society of Glass Technology elevated Dr. Varshneya to the rank of Honorary Fellow of the Society of Glass Technology ("Hon. FSGT"). The following was the citation:

  • "Your educational work at Alfred including your championing of the teaching of business skills to technologists, your industrial experience with Ford, GE and latterly, your own company Saxon Glass Technologies and your authorship of research papers and books together with many personal attributes too numerous to mention, all contributed to the view that you should be an Honorary Fellow of the Society."
  • There are only 12 total individuals with this distinction worldwide.

Dr. Varshneya was highlighted in two recent articles in Chemical & Engineering News:

  • Volume 96 Issue 3 | pp. 16-17
    • Issue Date: January 15, 2018
    • Article title: "Chemically strengthened glass finds a new application"
    • The science of chemical strengthening is relatively simple,” says Arun K. Varshneya, president of Saxon Glass Technologies. Immersing glass in a molten salt bath, typically potassium nitrate at around 450 °C, causes potassium ions to replace some of the sodium ions in a (few) micrometer-thick layer on the glass surface. The difference in ion size (K+’s radius is roughly 0.38 ? larger than that of Na+) leads to compressive forces that toughen the surface by blocking the routes along which cracks could otherwise propagate.
    • In principle, the ion-exchange process works with any glass that contains sodium, and most glass does. Soda-lime glass, for example, which is made from silica, sodium carbonate (soda ash), and calcium carbonate (limestone), accounts for 90% of all manufactured glass.
    • In the 1990s, Saxon Glass customized the process to strengthen 1-mm-thick sodium borosilicate glass cartridges used in EpiPen injectors. The devices deliver epinephrine to treat life-threatening anaphylactic shock caused by severe allergic reactions. Varshneya notes that before the strengthened cartridges were developed, as many as one in 10 broke during injection. The failure rate for the strengthened glass version is less than one in a million, he says, adding that last year the company sold 30 million such cartridges.
  • Volume 95 Issue 47 | pp. 28-29 | What's That Stuff?
    • Issue Date: November 27, 2017 | Web Date: November 22, 2017
    • Article title: "What’s glass, and how are modern-day researchers enhancing its properties?"
    • Why glass is still capturing the minds of scientists and innovators depends on whom you ask. Arun K. Varshneya, president of Saxon Glass Technologies, which specializes in strengthening glass for the pharmaceutical and other industries, ticks off a long list of properties that make the stuff so useful. Beyond being transparent, it also stands up to wind, rain, snow, intense sunlight, and large swings in temperature, he says. It’s also chemically resistant and recyclable, and many varieties of glass are relatively inexpensive.

Recent Awards:

  • Dr. Varshneya receives the Toledo Glass & Ceramics Award; delivers lecture entitled, “Strengthened Glasses”, Toledo OH, April 09, 2015.
  • Dr. Varshneya receives the 2015 Arthur L. Friedberg Memorial Lecture award; delivers a presentation entitled, “Principles of Glass Chemical Strengthening Science & Technology”, MS&T’15, Columbus OH, October 05, 2015.

Recent Presentations:

  • “Principles of glass chemical strengthening science and technology”, Invited graduate seminar at Rutgers, The State University, Piscataway NJ. April 25, 2017.
  • “Recent advances in the chemical strengthening of glass”, keynote lecture at the joint meeting of the International Conference on Advances in Glass Science & Technology (ICGAST) and the International Commission on Glass, Kolkata, January 23, 2017.
  • “Strengthened glass vs. sapphire as cover screens for personal electronic communication devices”, with Peter P. Bihuniak. Invited lecture at the ICGAST- ICG, Kolkata January 24, 2017. Also invited at the Materials Science & Technology 2016, Salt Lake City UT, October 27, 2016.
  • “Recent advances in the chemical strengthening of glass”, Invited at the Turner Legacy Symposium, Society of Glass Technology Centennial meeting, Sheffield (UK), September 06, 2016.

Recent Publications:

  • “Buildup and relaxation of stress in chemically strengthened glass”, Arun K. Varshneya, Garrett A. Olson, Patrick K. Kreski and Prabhat K. Gupta, J. Non-Cryst. Sol. 427, p 91-97 (2015).
  • “Mechanical model to simulate buildup and relaxation of stress during glass chemical strengthening”, Arun K. Varshneya, J. Non-Cryst. Sol. 433, p 28-30 (2016).

Recent Patents:

  • “Transparent armor systems, methods for making and methods for using”, Arun K. Varshneya and Patrick K. Kreski, US patent 9,162,426 B2 October 20, 2015.
  • “Method for making strengthened glass”, US patent 8,959,953 B2, February 24, 2015.
  • “Strengthened glass and curvature control”, Patrick K. Kreski, US 9,302,938, April 5, 2016.


  • Teamed up with Professor Edgar D. Zanotto of the Federal University of Sao Carlos, Brazil to deliver a 6-hour short course on “Sheffield alumni teachings on glass science and technology”, September 04, 2016. Twenty-six students from all parts of the world attended.
 More Patents, Publications, and Presentations
Dr. Varshneya honored with the 2014 Distinguished Life Membership award of the American Ceramic Society at the annual meeting October 13, 2014, Pittsburgh PA.

Dr. David Green, president of the American Ceramic Society presenting the award to Dr. Varshneya

Dr. Varshneya, accepting the honor, pays tribute to his late father, Nathi Lal Varshneya (picture in the background).

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Saxon Glass Technologies, Inc.P.O. Box 575200 N. Main St.Alfred, New York 14802

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