Records of the Royal Society for India, Pakistan and Ceylon, and its predecessors, the East India Association, National Indian Association and the India Society) are among the British Library, India Office Records: Private Papers (ref. Mss Eur F140 - Mss Eur F157) held at the British Library, Asia, Pacific and Africa Collections (previously Oriental and India Office Library) -see online catalogue. 

Online catalogue.

Further records of the East India Association (refs. IOR/L/I/1/58; IOR/L/I/1/59; IOR/L/I/1/60) are among the British Library, India Office Records: Information Department Records (see A2A)

Records of the Glasgow East India Association (dates 1812-47) are held at
Archives and Special Collections, The Mitchell Library -see NRA record.

There are numerous more minor references to the East India Association listed on A2A and Archives Hub. Further minor references to the National Indian Association and the India Society are listed on A2A.