For decomposition of azo compounds you can follow this.

DOI:10.1016/j.dyepig.2018.08.052

For decomposition of azo compounds you can follow this.

DOI: 10.1021/ja01505a025

For stable azo compounds you can follow this

DOI:10.1016/j.dyepig.2018.08.052

1- A.A.John and Q.Lin,Org.Chem. 2017, 82,9873-9876

2- M.H.Kim and J.Kim, Org.Chem.,2018,83,1673-1679.

The azo compounds are prepared by the amino acid reaction with hydrochloric acid and sodium nitrite to form the diazonium salts. The reaction is done at 0 ° C and then the solution is added to the drip with the constant stirring to the compound of the duplex with sodium hydroxide. It is very important to maintain the temperature of the solution 0 ° C so as not to dissolve the azo .

Regards

Don't heat it, it's better to deal with it at room or lower temperature. And aromatic azo compounds will be more stable.