It is narrated from Abd al-Rahman bin Abi Layla (may Allah have mercy on him) that Bilal (may Allah be pleased with him) was ordered to say 'As-salatu khayrun min an-nawm' (Prayer is better than sleep) in the morning prayer, and he was not ordered to say 'As-salatu khayrun min an-nawm' (Prayer is better than sleep) in any other.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1988
(a) It is narrated from Sayyiduna Bilal (may Allah be pleased with him) that he said: The Messenger of Allah (peace and blessings be upon him) ordered me: "That I should not perform tathwib (in any other adhan) besides Fajr."
(b) It is narrated from Suwayd bin Ghafalah (may Allah have mercy on him) that Sayyiduna Bilal (may Allah be pleased with him) did not perform tathwib except in Fajr; in his adhan he would say: 'Hayya 'ala al-falah, as-salatu khayrun min an-nawm' (Come to success; prayer is better than sleep).
This too is mursal, for Abd al-Rahman bin Abi Layla did not meet Bilal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1989
It is narrated from Mujahid that he said: I was with Sayyiduna Ibn Umar (may Allah be pleased with them both) when a man performed tathwib in Zuhr or Asr, so he said: Take us out (of here), for this is an innovation.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1990