Dear Mr. Paul,

With the material properties of borosilicate glass known, transient thermal analysis can be done in ANSYS. Unlike isotropic material, an orthotrotopic material is specified by coefficients along each direction. If orthotropy is simplified as isotropy, thermal analysis may give unscrupulous results. Since ANSYS is capable of accepting true nature of material, it is best to use orthotropic properties. In ANSYS material properties can be specified either at the beginning of analysis for all the elements or for individual elements. Main Menu---> Pre-processor--> Material Properties-->Material Models-->Orthortropic. I prefer to use ANSYS inbuilt library for material properties else you could look into MATWEB.

I hope this helps.

Best,

Digvijay

I have seen many papers taking glass as isotropic nature, though it is amorphous. But am not bale to find the orthotropic properties of glass for inputting the same in my model

I searched borosilicate glass on MATWEB and it gave me a bunch of options.

http://www.matweb.com/search/QuickText.aspx?SearchText=Borosilicate%20glass

The glass is disordered system, it should be considered isotropic  

What do you mean by disordered system? Can you explain how it is related to isotropic system? it will be of great help in my research works