Process for producing glass product having gradient of refractive index

摘要: It is known to make glass products, especially rods for use in facsimile and LED lens arrays, which have a gradient of refractive index between their central peripheral portions by permeating into micropores porous borosilicate solution dopant, e.g. CsNO3, or Pb(NO3)2 an amount up 40g/100ml water, leaching out part the dopant form desired solidifying pores drying rod heat treating collapse pores. To provide high without causing instability during treatment with loss transparency, now used TIN03; if alkali metal compound, CsNO3 therewith concentration TIN03 can be increased from not more than 80g TlNO/100 ml water 100 400 g/100 ml; preferably lead nitrate also used.