Glass Committee Terminology;... Indentation

Since my induction into the Glass Committee of the IWCA I have been pouring over many "white papers" sent my way by Paul West the current committee chair.  These are scientific research papers that discus glass surface test results.  However if someone didn't understand the terminology used they might as well have been written in another language.  So that we all can have a much better understanding of the details of the research Penn State has been working on for the IWCA Glass Committee I have decided to write a series of artcles/posts in the Glass Smart Blog called Glass Committee Terminology.

INDENTATION: 

This is a deep notch or depression on a surface.  Some words that define it are hollow, dip, dent, cavity, or pit. Here is a link to an excellent very technical article on nanoindentation technology.  Which is the kind employed by Penn State.  

http://szft.elte.hu/oktat/www/mikronano/Nano_indentation.pdf

It also discusses microindentation.  Indentation is the means by which certain mechanical properties of solid surfaces are measured, in particular hardness.  Which is what the GC was interested in using to learn about how the hardness of glass surfaces might change when subjected to different conditions of Relative Humidity (RH). Also they wanted to learn what glass surface hardness might be when the sodium atoms in particular have been selectively removed. This is important information since every scratch begins with a point of indentation.

Written by Henry Grover Jr.