Photomeric Calculations

Anisotropy in glass - what is it?

Optical anisotropy in glass refers to the undesired visual distortion of color that appears on glass in the presence of polarized light.  The term "anisotropy" means the directional dependence of a  physical property or properties of a material, in this case glass.  With most available thermally treated glass, the light which passes through the glass experiences double refraction, also called birefringence.  This is the anisotropy which distorts the appearance of glass.  Optical anisotropy appears as bands of discoloration, ribbons, rings, stripes, or leopard spots.  This anisotropic effect almost always occurs with heat treated glass, and the thicker the glass, the more apparent the anisotropy.  When glass is treated with heat to increase its toughness, the internal redistribution of stresses creates characteristic polarization bands, stripes, spots, or rings. This anisotropic effect in glass can become very pronounced when the glass is viewed at certain angles, under certain lighting conditions, or when viewed through polarized sunglasses.  The effect of unwanted anisotropy can cause distracting visual distortions on glass surfaces which detract from the overall aesthetic of the architect's design and creates an unpleasant visual disharmony.

arcon topview glass overcomes annoying anisotropy

Until only recently, the problem of anisotropy in tempered glass was simply a fact that architects and designers had come to tolerate.  Due to the redistribution of internal stress in thermally treated glass, there was simply no way to avoid the visual appearance of polarization bands, stripes, spots, or rings.  However, arcon topview glass is setting a new standard in eliminating visual anisotropy with its ESG (Tempered Safety Glass) and TVG (Heat Strengthened Glass) products.  With its patented innovative process engineering, arcon has achieved a line of thermally treated glass products with such slight levels of anisotropy that the human eye doesn't perceive it as annoying.  The result is a harmonious optical appearance for the glass which enhances the overall design and structure.

arcon topview glass sets a new standard for measuring isotropy in glass

"Isotropy" is a physics term which means uniformity in all directions - the opposite of anisotropy.  For glass with a high isotropic rating, the result is an undistorted optical effect, without undesired refraction spots or bands.  New measuring technology has been developed by arcon to quantitatively measure and rate the isotropy value of glass.  Using new isotropy measuring technology, arcon is now in a position to produce better tempered glass, and to verify and document the improved performance of the products.  The general standard tempered glass available on the market has isotropy values of 55 to 80%.  arcon topview ESG and TVG demonstrate a remarkable isotropy value of more than 95%.  With this incredible innovation in glass materials process manufacturing, arcon is poised as a pioneer leading the industry in anisotropy reduction.  At last, arcon topview glass has brought the search for beautiful glass within reach.

sleek, modern, elegant: arcon topview glass in architectural application

In a stunning modern design, arcon topview glass has been implemented and installed in the sweeping geometric glass design of the new Alubau Puhlmann administration building in Rhede.  This project is a prime showcase for the incredible visual clarity and harmony achieved by arcon topview glass products.  The effects of anisotropy are so low that they are no longer bothersome.  With a vast and lofty two-storey glass intensive construction, the design feels ambitious, stately, and utterly modern.  With the use of arcon topview glass, which has also been treated with suitable solar protection coatings, the architect has created a thoroughly modern, sophisticated building with a light elegance and a solid presence.  In addition to the enduring visual appeal, the building is energy efficient and has a sustainable view of the future. 

why choose arcon glass?

Good architectural glass conserves valuable resources, offers environmental protection, enables optimal climate control, provides stability and transparency, achieves the designer's aesthetic vision, and meets or exceeds safety standards.  With these fundamentals in mind, arcon creates architectural glass products and custom solutions for any imaginable application.

arcon offers the largest selection of solar control and low-e coatings available.  Good architectural glass conserves resources, and arcon offers the widest selection of high performance glass available. 

arcon enables flexible production to suit customer's needs, and creates custom solutions.

arcon can combine features of different products to obtain the perfect solutions.

subsequent delivery for many years
arcon offers the possibility of subsequent product delivery for older buildings.

arcon topview
arcon's topview glass is the only commercially available glass which eliminates visible anisotropy.

resources and references

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arcon topview glass without disturbing anisotropies
Glass facade with anisotropies - birefringence in the glass
Glass facade without anisotropy (polarization fields)