Contributo in atti di convegno, 2011, ENG, 10.1117/12.896758

Fused silica long term stability: case studies

Vannoni Maurizio ; Sordini Andrea ; Molesini Giuseppe

CNR-Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze

The time stability of fused silica is investigated, reporting new data on two flats that were purchased in 1981. It is found that their present shape is no more plane, exhibiting instead a concavity that is compatible with a very slow laminar flow under the action of gravity. The data are examined altogether with those of prior observations, confirming the occurrence of a relaxation process whose time constant is estimated in the order of 10 years; during such a time period, viscosity approximately increases by a factor of three. Starting from the experimental data so far collected, the computations accounting for the estimates above are given in detail.

Conference on Optical Fabrication, Testing, and Metrology IV, pp. 816906–816906, Marseille, FRANCE, September 07-08 2011

Keywords

Optical testing, fused silica, long-term stability

CNR authors

Molesini Giuseppe, Vannoni Maurizio, Sordini Andrea

CNR institutes

INO – Istituto nazionale di ottica