This website provides a thorough explanation of using a polariscope and technical information about strain in glass: https://web.archive.org/web/20080509130605/https://www.garnerglass.com/index.htm
I have attached a bibliography of resources about using a polariscope, including the following article:
"Polariscope: Viewing the Stress in Glass." Glass Line, v. 2, no. 5, Feb./March 1989, pp. 11-14.
I am not familiar with the product you mentioned: "Strain Viewer with standard Strain Disc set of 5 No." You may wish to write to the company that made the viewer to ask for more instructions.
Tooley is a very good source for glass making information. Volume 2, pp. 956-2 -- 956-4 covers stress in glass.
I've attached a list of other books that may be useful. They may be available for sale via internet book sites.
I will look for more information about phase diagrams. It is beyond the scope of our museum library to answer very technical questions in detail (our library focuses more on the art and history of glass, with some technical information).
You may wish to contact one of the following organizations:
1)The Scholes Library at Alfred University, New York State College of Ceramics. They have a substantial collection of technical information about glass. Pat Lacourse answers technical reference questions (email:lacourpc@alfred.edu). Their reference desk number is: 607-871-2951. Their library catalog is available for searching on the web: https://scholes.alfred.edu.
2) The Glass Division of the American Ceramic Society (Columbus, Ohio) Website: https://www.acers.org/ The American Ceramic Society, P.O. Box 6136, Westerville, Ohio 43086-6136 ; Phone: 614/890-4700 ; FAX: 614/899-6109 ; E-Mail: info@acers.org
3) The Society of Glass Technology in Sheffield, UK: Website: https://www.societyofglasstechnology.org.uk/; Don Valley House, Savile Street East, Sheffield S4 7UQ, UK ;Tel: +44(0)114 263 4455 ; Fax +44(0)114 263 4411 ; e-mail: info@sgt.org
