1 / 11

The Science of Glass

The Science of Glass. http://openplac.es/trips/visiting-the-glass-blowing-workshops-in-murano-italy. Three Main components:. Formers Fluxes Stabilizers. Typically silica (SiO 2 ) in the form of sand. Melts at a very hot temperature. An alkali to lower the temperature of viscosity.

chip
Download Presentation

The Science of Glass

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Science of Glass http://openplac.es/trips/visiting-the-glass-blowing-workshops-in-murano-italy

  2. Three Main components: Formers Fluxes Stabilizers Typically silica (SiO2) in the form of sand. Melts at a very hot temperature. An alkali to lower the temperature of viscosity. Sodium carbonate plant ash (Na2CO3) http://bdreaper.com/ Make the glass strong and water resistant (glass is polar without it) Limestone (CaCO3) http://www.gem-projects.be/gem%20RMbody.htm

  3. Bridging oxygen (no charge) Non-Bridging oxygen (negative charge) Tetrahedral Molecular Geometry The tetrahedrals form a network of chains which the sodium disrupts. • Pollard, Archaeological Chemistry, 2008 (http://www.chemguide.co.uk/CIE/section4/learningfg.html)

  4. Physical characteristics The structural rigidity of a solid but the random molecular arrangement of a liquid (no melting point –Supercooled liquid) • http://www.cmog.org/article/what-is-glass

  5. Glass has no melting point and no distinct transition from liquid to solid. Crystal transitions from liquid to solid. Melting point of crystal. • Paul, 1990, Fig. 102

  6. Why does glass crack when it goes quickly from hot to cold? Glass has a high thermal expansion coefficient (it expands a lot when heated because of its loose structure (compared with other solids)

  7. Additives (optional) • Boron makes glass heat resistant (lab glass, cooking glass etc.) • Lead makes glass shiny – crystal • Colors - different colors can be added to the glass by the addition of powdered transition metal oxides. • Cobalt – blue Copper – blue/green Chromium - green • Titanium – yellow Manganese – purple Nickel - gray • http://www.rci.rutgers.edu/~glasseng/CourseLinks/ColorGlasEng.pdf

  8. What are some of the considerations of glass blowing? Heating– glass has no distinct melting point so temperatures are defined by viscosity. The flux lowers the temperature at which glass becomes workably viscous. Holloway, 1973, 19

  9. Popping air into glass – small amounts of air are introduced and the heat expands • Cooling – thicker parts of glass stay hotter longer than thinner parts of glass so the glass must be cooled very slowly through a process called “Annealing”

  10. What is the history of glass? • 2000 BC First examples of glass from the Mesopotamians. • 50 BC Romans invented glass blowing which made the process faster and more affordable. • 1100-1600 needed colored glass for stained glass windows and used beech ash as the flux, which is water soluble. (Makes cleaning very difficult). • 1800s- Made stained glass windows by painting on layers of transition metal oxides in borax. Borax is also water soluble which makes the colors dissolve away with cleaning. • http://www.buildingconservation.com/articles/cleaning-stained-glass/cleaning-stained-glass.htm

  11. http://books.google.com/books?id=CT_FWEfanCIC&printsec=frontcover#v=onepage&q&f=falsehttp://books.google.com/books?id=CT_FWEfanCIC&printsec=frontcover#v=onepage&q&f=false • http://www.cmog.org/video/annealing-and-tension-glass • http://www.pilkington.com/pilkington-information/about+pilkington/education/chemistry+of+glass.htm • http://www.asmallproduction.com/How-To-Make-Hand-Blown-Glass-Pumpkins.html • http://sites.duke.edu/dukeresearch/files/2011/10/0729-sci-GLASSb.gif • http://www.rci.rutgers.edu/~glasseng/CourseLinks/ColorGlasEng.pdf • http://timeline.cmog.org/ http://www.astarwasborn.com/glass-blowing-classes-in-portland-oregon/

More Related