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Photochromic Glass for Ophthalmology

#0762


New Photochromic Glass for Ophthalmology

Tech Area / Field

  • MAT-SYN/Materials Synthesis and Processing/Materials

Status
3 Approved without Funding

Registration date
08.10.1996

Leading Institute
Vavilov State Optical Institute (GOI), Russia, St Petersburg

Supporting institutes

  • PO LZOS (Optical Glass Plant), Russia, Moscow reg., Lytkarino\nU 61469, Russia, Saratov reg., Volsk-18

Collaborators

  • VITCON Projectconsult GmbH, Germany, Jena

Project summary

The project goal is:
a) to develop new cuprous halide commercial photochromic glass which combines the advantages of the best foreign photochromic glasses (high speeds of darkening and relaxation) and of Russian glass ФХС8 (absence of ecological harmful cadmium, extremely high UV-protection, extended spectral sensitivity band up to 1000 nm, photochromic efficiency at temperatures above 30 °C). It will be used in sunprotective goggles for some eye illness treatment and prevention, as well as in inpidual protection means for firemen;
b) to develop the suggestions of glass applications to the building, transport and civilian optical devices (to extend its dynamic exposition range under accidental parasite light exposure).

Expected results:


- Technology of new competitive cuprous halide photochromic glass ensuring an effective VIS- and a perfect UV-protection against sunlight and a number of colored photochromic glasses as well. It has an extended sphere of use, has no analogies, ensures an ecological purity of glass production (excluding cadmium oxide out of composition). Sunprotective parameters: visual transmission in the darkened state is not more then 20 %,after thermal fading in darkness it becomes not less then 74 % (at room temperature); efficient above 30 °C; its coefficient of UV-weakening is equal to 1015 at 370 nm (by twelve orders more then that of silver halide photochromic glass) and 1010 at 350 nm;
- Mock-up of inpidual protective mean against fire flame meeting the medical eye protective requirements;
- New experimental data on supersmall crystals in matrix glass: properties of excitons, the interaction excitons with phonons, thermal and radioactive defects, as well as phase creation kinetics and energy spectrum of traps responsible for speed of thermal fading; new original research technique of ultradispersed medium physics and nanotechnology;
- Theoretical model of complicated thermal and mass exchange in photochromic glass melt under high-frequency heating; the construction of particular induction melting furnace with 2-5 liter crucibles for photochromic glass which allows to minimize the lightsensitive additions evaporation;
- The results of long-term analysis of new glass perspective applications in transport, building and civilian optical instrument-making.

The project realization lays theoretical, experimental and technological foundation for petty production of photochromic filter of high optical quality and profitable large-scaled production. That permits to establish production of commercial photochromic glass and sunprotective ophthalmic lens in Russia.

Technical Approach and Methodology:

For solving the project problems there will be used scientific and technical developments of ARSC "S.I.Vavilov State Optical Institute" in the following spheres:


- physiological optics and eye protection against light damages;
- technology of new glass-crystal photosensitive materials with particular properties;
- photochemistry of ionic crystals and the theory of photographic process;
- the latest basic investigations of physical nature and mechanisms of photo-electron and ionic processes in cuprous and silver halides in glass matrix by photolysis and luminescence methods as well as exciton interaction with phonons, thermal and radioactive defects and energy structure of traps;
- the latest physical-chemical investigations of the valence state of activators in matrix glass, their role in formation of photosensitive crystal phase and in kinetics of liquid-solid transition;
- theoretical thermophysics in complicated heat exchange sphere and the practice of optical glass melting in high-frequency furnaces;
- development of electronic means of light action control and simulation, as well as electronic-optical protective means against light flux, including light radiation of fire flame.

In order to develop the reproducible glass technology and to study the structure, the photochemical sensitivity of crystal phase there will be used a number of research methodic at the same time:


a) usual for glass-crystal objects phase X-ray (XPA) and microdiffractive (MDA) analysis, electron microscopy (EM), small-angled X-ray dispersion (DSA), differentially scanned coloriemetry (DSC) and
b) spectrometric methods of electron spin resonance (ESR) and nuclear gamma-resonance (NGR), optical (OS) and exciton spectroscopy (ES).

New research methodic will be developed and applicated to study the melting-crystallization transitions in cuprous halide phase by means of spectroscopic measurements at Urbach's point (ESU).

Potential role of foreign collaborators:

The support to project has been rendered by the Company VITCON Project consult GmbH (Jena, Germany). It is proposed the joint investigation of new glass samples and the joint evaluation of their properties, scientific and tech-nical information exchange, the definition of new applications of glass.

We are also hopeful for co-operation with the other foreign partners in the part of exchanging of the results obtained, of joint work at project and of financial project support in the sphere of glass technology, crystal state physics and electrooptical protective devices against light flux.


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