CHEM 4100 / Assignment 1

Stable glasses used in architecture and household ware are at one ned of the compositional range, while towards lower silica contents, the glasses become less stable and can be partially/fully dissolved in aqueous solutions.

Crystallization tendency increases, as silica content decreases.

Soda lime silicate glasses do promote in vivo bone formation if the silica content is low.

Decrease in silica content → affects atomic arrangement → change in properties from bio-inert to bio-active

NMR: broad peak between -60 and -105 ppm; max position at upfield with decreasing silicate content. Less silicate, more upfield. Less silicon in NMR, less downfield effects. → Depolymerized.

Qⁿ groups = n is the # of bridging oxygen atoms connected to central silicon atom

More network modified contents (sodium and calcium oxide) → turn BO into NBO (-Si-O^- M⁺ where M⁺ is modifier cation)

Si70 dominated with Q3 species and minor with Q4 and Q2 = typical 3D silicate network.